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ac | ac(1) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training ac(1) Linux manual page NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | AUTHOR | SEE ALSO | COLOPHON AC(1) General Commands Manual AC(1) NAME top ac - print statistics about users' connect time SYNOPSIS top ac [ -d | --daily-totals ] [ -y | --print-year ] [ -p | --individual-totals ] [ people ] [ -f | --file filename ] [ -a | --all-days ] [ --complain ] [ --reboots ] [ --supplants ] [ --timewarps ] [ --compatibility ] [ --tw-leniency num ] [ --tw-suspicious num ] [ -z | --print-zeros ] [ --debug ] [ -V | --version ] [ -h | --help ] DESCRIPTION top ac prints out a report of connect time (in hours) based on the logins/logouts in the current wtmp file. A total is also printed out. The accounting file wtmp is maintained by init(8) and login(1). Neither ac nor login creates the wtmp if it doesn't exist, no accounting is done. To begin accounting, create the file with a length of zero. NOTE: The wtmp file can get really big, really fast. You might want to trim it every once and a while. GNU ac works nearly the same UNIX ac, though it's a little smarter in several ways. You should therefore expect differences in the output of GNU ac and the output of ac's on other systems. Use the command info accounting to get additional information. OPTIONS top -d, --daily-totals Print totals for each day rather than just one big total at the end. The output looks like this: Jul 3 total 1.17 Jul 4 total 2.10 Jul 5 total 8.23 Jul 6 total 2.10 Jul 7 total 0.30 -p, --individual-totals Print time totals for each user in addition to the usual everything-lumped-into-one value. It looks like: bob 8.06 goff 0.60 maley 7.37 root 0.12 total 16.15 people Print out the sum total of the connect time used by all of the users included in people. Note that people is a space separated list of valid user names; wildcards are not allowed. -f, --file filename Read from the file filename instead of the system's wtmp file. --complain When the wtmp file has a problem (a time-warp, missing record, or whatever), print out an appropriate error. --reboots Reboot records are NOT written at the time of a reboot, but when the system restarts; therefore, it is impossible to know exactly when the reboot occurred. Users may have been logged into the system at the time of the reboot, and many ac's automatically count the time between the login and the reboot record against the user (even though all of that time shouldn't be, perhaps, if the system is down for a long time, for instance). If you want to count this time, include the flag. *For vanilla ac compatibility, include this flag.* --supplants Sometimes, a logout record is not written for a specific terminal, so the time that the last user accrued cannot be calculated. If you want to include the time from the user's login to the next login on the terminal (though probably incorrect), include this you want to include the time from the user's login to the next login on the terminal (though probably incorrect), include this flag. *For vanilla ac compatibility, include this flag.* --timewarps Sometimes, entries in a wtmp file will suddenly jump back into the past without a clock change record occurring. It is impossible to know how long a user was logged in when this occurs. If you want to count the time between the login and the time warp against the user, include this flag. *For vanilla ac compatibility, include this flag.* --compatibility This is shorthand for typing out the three above options. -a, --all-days If we're printing daily totals, print a record for every day instead of skipping intervening days where there is no login activity. Without this flag, time accrued during those intervening days gets listed under the next day where there is login activity. --tw-leniency num Set the time warp leniency to num seconds. Records in wtmp files might be slightly out of order (most notably when two logins occur within a one-second period - the second one gets written first). By default, this value is set to 60. If the program notices this problem, time is not assigned to users unless the --timewarps flag is used. --tw-suspicious num Set the time warp suspicious value to num seconds. If two records in the wtmp file are farther than this number of seconds apart, there is a problem with the wtmp file (or your machine hasn't been used in a year). If the program notices this problem, time is not assigned to users unless the --timewarps flag is used. -y, --print-year Print year when displaying dates. -z, --print-zeros If a total for any category (save the grand total) is zero, print it. The default is to suppress printing. --debug Print verbose internal information. -V, --version Print the version number of ac to standard output and quit. -h, --help Prints the usage string and default locations of system files to standard output and exits. FILES top wtmp The system wide login record file. See wtmp(5) for further details. AUTHOR top The GNU accounting utilities were written by Noel Cragg <noel@gnu.ai.mit.edu>. The man page was adapted from the accounting texinfo page by Susan Kleinmann <sgk@sgk.tiac.net>. SEE ALSO top login(1), wtmp(5), init(8), sa(8) COLOPHON top This page is part of the psacct (process accounting utilities) project. Information about the project can be found at http://www.gnu.org/software/acct/. If you have a bug report for this manual page, see http://www.gnu.org/software/acct/. This page was obtained from the tarball acct-6.6.4.tar.gz fetched from http://ftp.gnu.org/gnu/acct/ on 2023-12-22. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org 2010 August 16 AC(1) Pages that refer to this page: utmp(5), accton(8), sa(8) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # ac\n\n> Print statistics on how long users have been connected.\n> More information: <https://www.gnu.org/software/acct/manual/accounting.html#ac>.\n\n- Print how long the current user has been connected in hours:\n\n`ac`\n\n- Print how long users have been connected in hours:\n\n`ac --individual-totals`\n\n- Print how long a particular user has been connected in hours:\n\n`ac --individual-totals {{username}}`\n\n- Print how long a particular user has been connected in hours per day (with total):\n\n`ac --daily-totals --individual-totals {{username}}`\n\n- Also display additional details:\n\n`ac --compatibility`\n |
addpart | addpart(8) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training addpart(8) Linux manual page NAME | SYNOPSIS | DESCRIPTION | PARAMETERS | SEE ALSO | REPORTING BUGS | AVAILABILITY ADDPART(8) System Administration ADDPART(8) NAME top addpart - tell the kernel about the existence of a partition SYNOPSIS top addpart device partition start length DESCRIPTION top addpart tells the Linux kernel about the existence of the specified partition. The command is a simple wrapper around the "add partition" ioctl. This command doesnt manipulate partitions on a block device. PARAMETERS top device The disk device. partition The partition number. start The beginning of the partition (in 512-byte sectors). length The length of the partition (in 512-byte sectors). -h, --help Display help text and exit. -V, --version Print version and exit. SEE ALSO top delpart(8), fdisk(8), parted(8), partprobe(8), partx(8) REPORTING BUGS top For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues. AVAILABILITY top The addpart command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>. This page is part of the util-linux (a random collection of Linux utilities) project. Information about the project can be found at https://www.kernel.org/pub/linux/utils/util-linux/. If you have a bug report for this manual page, send it to util-linux@vger.kernel.org. This page was obtained from the project's upstream Git repository git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git on 2023-12-22. (At that time, the date of the most recent commit that was found in the repository was 2023-12-14.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org util-linux 2.39.594-1e0ad 2023-07-19 ADDPART(8) Pages that refer to this page: delpart(8), partx(8), resizepart(8) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # addpart\n\n> Tell the Linux kernel about the existence of the specified partition.\n> A simple wrapper around the `add partition` ioctl.\n> More information: <https://manned.org/addpart>.\n\n- Tell the kernel about the existence of the specified partition:\n\n`addpart {{device}} {{partition}} {{start}} {{length}}`\n |
addr2line | addr2line(1) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training addr2line(1) Linux manual page NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT | COLOPHON ADDR2LINE(1) GNU Development Tools ADDR2LINE(1) NAME top addr2line - convert addresses or symbol+offset into file names and line numbers SYNOPSIS top addr2line [-a|--addresses] [-b bfdname|--target=bfdname] [-C|--demangle[=style]] [-r|--no-recurse-limit] [-R|--recurse-limit] [-e filename|--exe=filename] [-f|--functions] [-s|--basename] [-i|--inlines] [-p|--pretty-print] [-j|--section=name] [-H|--help] [-V|--version] [addr addr ...] DESCRIPTION top addr2line translates addresses or symbol+offset into file names and line numbers. Given an address or symbol+offset in an executable or an offset in a section of a relocatable object, it uses the debugging information to figure out which file name and line number are associated with it. The executable or relocatable object to use is specified with the -e option. The default is the file a.out. The section in the relocatable object to use is specified with the -j option. addr2line has two modes of operation. In the first, hexadecimal addresses or symbol+offset are specified on the command line, and addr2line displays the file name and line number for each address. In the second, addr2line reads hexadecimal addresses or symbol+offset from standard input, and prints the file name and line number for each address on standard output. In this mode, addr2line may be used in a pipe to convert dynamically chosen addresses. The format of the output is FILENAME:LINENO. By default each input address generates one line of output. Two options can generate additional lines before each FILENAME:LINENO line (in that order). If the -a option is used then a line with the input address is displayed. If the -f option is used, then a line with the FUNCTIONNAME is displayed. This is the name of the function containing the address. One option can generate additional lines after the FILENAME:LINENO line. If the -i option is used and the code at the given address is present there because of inlining by the compiler then additional lines are displayed afterwards. One or two extra lines (if the -f option is used) are displayed for each inlined function. Alternatively if the -p option is used then each input address generates a single, long, output line containing the address, the function name, the file name and the line number. If the -i option has also been used then any inlined functions will be displayed in the same manner, but on separate lines, and prefixed by the text (inlined by). If the file name or function name can not be determined, addr2line will print two question marks in their place. If the line number can not be determined, addr2line will print 0. When symbol+offset is used, +offset is optional, except when the symbol is ambigious with a hex number. The resolved symbols can be mangled or unmangled, except unmangled symbols with + are not allowed. OPTIONS top The long and short forms of options, shown here as alternatives, are equivalent. -a --addresses Display the address before the function name, file and line number information. The address is printed with a 0x prefix to easily identify it. -b bfdname --target=bfdname Specify that the object-code format for the object files is bfdname. -C --demangle[=style] Decode (demangle) low-level symbol names into user-level names. Besides removing any initial underscore prepended by the system, this makes C++ function names readable. Different compilers have different mangling styles. The optional demangling style argument can be used to choose an appropriate demangling style for your compiler. -e filename --exe=filename Specify the name of the executable for which addresses should be translated. The default file is a.out. -f --functions Display function names as well as file and line number information. -s --basenames Display only the base of each file name. -i --inlines If the address belongs to a function that was inlined, the source information for all enclosing scopes back to the first non-inlined function will also be printed. For example, if "main" inlines "callee1" which inlines "callee2", and address is from "callee2", the source information for "callee1" and "main" will also be printed. -j --section Read offsets relative to the specified section instead of absolute addresses. -p --pretty-print Make the output more human friendly: each location are printed on one line. If option -i is specified, lines for all enclosing scopes are prefixed with (inlined by). -r -R --recurse-limit --no-recurse-limit --recursion-limit --no-recursion-limit Enables or disables a limit on the amount of recursion performed whilst demangling strings. Since the name mangling formats allow for an infinite level of recursion it is possible to create strings whose decoding will exhaust the amount of stack space available on the host machine, triggering a memory fault. The limit tries to prevent this from happening by restricting recursion to 2048 levels of nesting. The default is for this limit to be enabled, but disabling it may be necessary in order to demangle truly complicated names. Note however that if the recursion limit is disabled then stack exhaustion is possible and any bug reports about such an event will be rejected. The -r option is a synonym for the --no-recurse-limit option. The -R option is a synonym for the --recurse-limit option. Note this option is only effective if the -C or --demangle option has been enabled. @file Read command-line options from file. The options read are inserted in place of the original @file option. If file does not exist, or cannot be read, then the option will be treated literally, and not removed. Options in file are separated by whitespace. A whitespace character may be included in an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) may be included by prefixing the character to be included with a backslash. The file may itself contain additional @file options; any such options will be processed recursively. SEE ALSO top Info entries for binutils. COPYRIGHT top Copyright (c) 1991-2023 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". COLOPHON top This page is part of the binutils (a collection of tools for working with executable binaries) project. Information about the project can be found at http://www.gnu.org/software/binutils/. If you have a bug report for this manual page, see http://sourceware.org/bugzilla/enter_bug.cgi?product=binutils. This page was obtained from the tarball binutils-2.41.tar.gz fetched from https://ftp.gnu.org/gnu/binutils/ on 2023-12-22. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org binutils-2.41 2023-12-22 ADDR2LINE(1) Pages that refer to this page: backtrace(3) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # addr2line\n\n> Convert addresses of a binary into file names and line numbers.\n> More information: <https://manned.org/addr2line>.\n\n- Display the filename and line number of the source code from an instruction address of an executable:\n\n`addr2line --exe={{path/to/executable}} {{address}}`\n\n- Display the function name, filename and line number:\n\n`addr2line --exe={{path/to/executable}} --functions {{address}}`\n\n- Demangle the function name for C++ code:\n\n`addr2line --exe={{path/to/executable}} --functions --demangle {{address}}`\n |
agetty | agetty(8) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training agetty(8) Linux manual page NAME | SYNOPSIS | DESCRIPTION | ARGUMENTS | OPTIONS | CONFIG FILE ITEMS | EXAMPLE | SECURITY NOTICE | ISSUE FILES | FILES | CREDENTIALS | BUGS | DIAGNOSTICS | AUTHORS | REPORTING BUGS | AVAILABILITY AGETTY(8) System Administration AGETTY(8) NAME top agetty - alternative Linux getty SYNOPSIS top agetty [options] port [baud_rate...] [term] DESCRIPTION top agetty opens a tty port, prompts for a login name and invokes the /bin/login command. It is normally invoked by init(8). agetty has several non-standard features that are useful for hardwired and for dial-in lines: Adapts the tty settings to parity bits and to erase, kill, end-of-line and uppercase characters when it reads a login name. The program can handle 7-bit characters with even, odd, none or space parity, and 8-bit characters with no parity. The following special characters are recognized: Control-U (kill); DEL and backspace (erase); carriage return and line feed (end of line). See also the --erase-chars and --kill-chars options. Optionally deduces the baud rate from the CONNECT messages produced by Hayes(tm)-compatible modems. Optionally does not hang up when it is given an already opened line (useful for call-back applications). Optionally does not display the contents of the /etc/issue file. Optionally displays an alternative issue files or directories instead of /etc/issue or /etc/issue.d. Optionally does not ask for a login name. Optionally invokes a non-standard login program instead of /bin/login. Optionally turns on hardware flow control. Optionally forces the line to be local with no need for carrier detect. This program does not use the /etc/gettydefs (System V) or /etc/gettytab (SunOS 4) files. ARGUMENTS top port A path name relative to the /dev directory. If a "-" is specified, agetty assumes that its standard input is already connected to a tty port and that a connection to a remote user has already been established. Under System V, a "-" port argument should be preceded by a "--". baud_rate,... A comma-separated list of one or more baud rates. Each time agetty receives a BREAK character it advances through the list, which is treated as if it were circular. Baud rates should be specified in descending order, so that the null character (Ctrl-@) can also be used for baud-rate switching. This argument is optional and unnecessary for virtual terminals. The default for serial terminals is keep the current baud rate (see --keep-baud) and if unsuccessful then default to '9600'. term The value to be used for the TERM environment variable. This overrides whatever init(1) may have set, and is inherited by login and the shell. The default is 'vt100', or 'linux' for Linux on a virtual terminal, or 'hurd' for GNU Hurd on a virtual terminal. OPTIONS top -8, --8bits Assume that the tty is 8-bit clean, hence disable parity detection. -a, --autologin username Automatically log in the specified user without asking for a username or password. Using this option causes an -f username option and argument to be added to the /bin/login command line. See --login-options, which can be used to modify this options behavior. Note that --autologin may affect the way in which getty initializes the serial line, because on auto-login agetty does not read from the line and it has no opportunity optimize the line setting. -c, --noreset Do not reset terminal cflags (control modes). See termios(3) for more details. -E, --remote Typically the login(1) command is given a remote hostname when called by something such as telnetd(8). This option allows agetty to pass what it is using for a hostname to login(1) for use in utmp(5). See --host, login(1), and utmp(5). If the --host fakehost option is given, then an -h fakehost option and argument are added to the /bin/login command line. If the --nohostname option is given, then an -H option is added to the /bin/login command line. See --login-options. -f, --issue-file path Specifies a ":" delimited list of files and directories to be displayed instead of /etc/issue (or other). All specified files and directories are displayed, missing or empty files are silently ignored. If the specified path is a directory then display all files with .issue file extension in version-sort order from the directory. This allows custom messages to be displayed on different terminals. The --noissue option will override this option. --show-issue Display the current issue file (or other) on the current terminal and exit. Use this option to review the current setting, it is not designed for any other purpose. Note that output may use some default or incomplete information as proper output depends on terminal and agetty command line. -h, --flow-control Enable hardware (RTS/CTS) flow control. It is left up to the application to disable software (XON/XOFF) flow protocol where appropriate. -H, --host fakehost Write the specified fakehost into the utmp file. Normally, no login host is given, since agetty is used for local hardwired connections and consoles. However, this option can be useful for identifying terminal concentrators and the like. -i, --noissue Do not display the contents of /etc/issue (or other) before writing the login prompt. Terminals or communications hardware may become confused when receiving lots of text at the wrong baud rate; dial-up scripts may fail if the login prompt is preceded by too much text. -I, --init-string initstring Set an initial string to be sent to the tty or modem before sending anything else. This may be used to initialize a modem. Non-printable characters may be sent by writing their octal code preceded by a backslash (\). For example, to send a linefeed character (ASCII 10, octal 012), write \12. -J, --noclear Do not clear the screen before prompting for the login name. By default the screen is cleared. -l, --login-program login_program Invoke the specified login_program instead of /bin/login. This allows the use of a non-standard login program. Such a program could, for example, ask for a dial-up password or use a different password file. See --login-options. -L, --local-line[=mode] Control the CLOCAL line flag. The optional mode argument is auto, always or never. If the mode argument is omitted, then the default is always. If the --local-line option is not given at all, then the default is auto. always Forces the line to be a local line with no need for carrier detect. This can be useful when you have a locally attached terminal where the serial line does not set the carrier-detect signal. never Explicitly clears the CLOCAL flag from the line setting and the carrier-detect signal is expected on the line. auto The agetty default. Does not modify the CLOCAL setting and follows the setting enabled by the kernel. -m, --extract-baud Try to extract the baud rate from the CONNECT status message produced by Hayes(tm)-compatible modems. These status messages are of the form: "<junk><speed><junk>". agetty assumes that the modem emits its status message at the same speed as specified with (the first) baud_rate value on the command line. Since the --extract-baud feature may fail on heavily-loaded systems, you still should enable BREAK processing by enumerating all expected baud rates on the command line. --list-speeds Display supported baud rates. These are determined at compilation time. -n, --skip-login Do not prompt the user for a login name. This can be used in connection with the --login-program option to invoke a non-standard login process such as a BBS system. Note that with the --skip-login option, agetty gets no input from the user who logs in and therefore will not be able to figure out parity, character size, and newline processing of the connection. It defaults to space parity, 7 bit characters, and ASCII CR (13) end-of-line character. Beware that the program that agetty starts (usually /bin/login) is run as root. -N, --nonewline Do not print a newline before writing out /etc/issue. -o, --login-options login_options Options and arguments that are passed to login(1). Where \u is replaced by the login name. For example: --login-options '-h darkstar -- \u' See --autologin, --login-program and --remote. Please read the SECURITY NOTICE below before using this option. -p, --login-pause Wait for any key before dropping to the login prompt. Can be combined with --autologin to save memory by lazily spawning shells. -r, --chroot directory Change root to the specified directory. -R, --hangup Call vhangup(2) to do a virtual hangup of the specified terminal. -s, --keep-baud Try to keep the existing baud rate. The baud rates from the command line are used when agetty receives a BREAK character. If another baud rates specified then the original baud rate is also saved to the end of the wanted baud rates list. This can be used to return to the original baud rate after unexpected BREAKs. -t, --timeout timeout Terminate if no user name could be read within timeout seconds. Use of this option with hardwired terminal lines is not recommended. -U, --detect-case Turn on support for detecting an uppercase-only terminal. This setting will detect a login name containing only capitals as indicating an uppercase-only terminal and turn on some upper-to-lower case conversions. Note that this has no support for any Unicode characters. -w, --wait-cr Wait for the user or the modem to send a carriage-return or a linefeed character before sending the /etc/issue file (or others) and the login prompt. This is useful with the --init-string option. --nohints Do not print hints about Num, Caps and Scroll Locks. --nohostname By default the hostname will be printed. With this option enabled, no hostname at all will be shown. This setting is also possible to able by LOGIN_PLAIN_PROMPT option in the /etc/login.defs configuration file (see below for more details). --long-hostname By default the hostname is only printed until the first dot. With this option enabled, the fully qualified hostname by gethostname(3P) or (if not found) by getaddrinfo(3) is shown. --erase-chars string This option specifies additional characters that should be interpreted as a backspace ("ignore the previous character") when the user types the login name. The default additional 'erase' has been '#', but since util-linux 2.23 no additional erase characters are enabled by default. --kill-chars string This option specifies additional characters that should be interpreted as a kill ("ignore all previous characters") when the user types the login name. The default additional 'kill' has been '@', but since util-linux 2.23 no additional kill characters are enabled by default. --chdir directory Change directory before the login. --delay number Sleep seconds before open tty. --nice number Run login with this priority. --reload Ask all running agetty instances to reload and update their displayed prompts, if the user has not yet commenced logging in. After doing so the command will exit. This feature might be unsupported on systems without Linux inotify(7). -h, --help Display help text and exit. -V, --version Print version and exit. CONFIG FILE ITEMS top agetty reads the /etc/login.defs configuration file (see login.defs(5)). Note that the configuration file could be distributed with another package (usually shadow-utils). The following configuration items are relevant for agetty: LOGIN_PLAIN_PROMPT (boolean) Tell agetty that printing the hostname should be suppressed in the login: prompt. This is an alternative to the --nohostname command line option. The default value is no. EXAMPLE top This section shows examples for the process field of an entry in the /etc/inittab file. Youll have to prepend appropriate values for the other fields. See inittab(5) for more details. For a hardwired line or a console tty: /sbin/agetty 9600 ttyS1 For a directly connected terminal without proper carrier-detect wiring (try this if your terminal just sleeps instead of giving you a password: prompt): /sbin/agetty --local-line 9600 ttyS1 vt100 For an old-style dial-in line with a 9600/2400/1200 baud modem: /sbin/agetty --extract-baud --timeout 60 ttyS1 9600,2400,1200 For a Hayes modem with a fixed 115200 bps interface to the machine (the example init string turns off modem echo and result codes, makes modem/computer DCD track modem/modem DCD, makes a DTR drop cause a disconnection, and turns on auto-answer after 1 ring): /sbin/agetty --wait-cr --init-string 'ATE0Q1&D2&C1S0=1\015' 115200 ttyS1 SECURITY NOTICE top If you use the --login-program and --login-options options, be aware that a malicious user may try to enter lognames with embedded options, which then get passed to the used login program. agetty does check for a leading "-" and makes sure the logname gets passed as one parameter (so embedded spaces will not create yet another parameter), but depending on how the login binary parses the command line that might not be sufficient. Check that the used login program cannot be abused this way. Some programs use "--" to indicate that the rest of the command line should not be interpreted as options. Use this feature if available by passing "--" before the username gets passed by \u. ISSUE FILES top The default issue file is /etc/issue. If the file exists, then agetty also checks for /etc/issue.d directory. The directory is optional extension to the default issue file and content of the directory is printed after /etc/issue content. If the /etc/issue does not exist, then the directory is ignored. All files with .issue extension from the directory are printed in version-sort order. The directory can be used to maintain 3rd-party messages independently on the primary system /etc/issue file. Since version 2.35 additional locations for issue file and directory are supported. If the default /etc/issue does not exist, then agetty checks for /run/issue and /run/issue.d, thereafter for /usr/lib/issue and /usr/lib/issue.d. The directory /etc is expected for host specific configuration, /run is expected for generated stuff and /usr/lib for static distribution maintained configuration. The default path maybe overridden by --issue-file option. In this case specified path has to be file or directory and all the default issue file and directory locations are ignored. The issue file feature can be completely disabled by --noissue option. It is possible to review the current issue file by agetty --show-issue on the current terminal. The issue files may contain certain escape codes to display the system name, date, time et cetera. All escape codes consist of a backslash (\) immediately followed by one of the characters listed below. 4 or 4{interface} Insert the IPv4 address of the specified network interface (for example: \4{eth0}). If the interface argument is not specified, then select the first fully configured (UP, non-LOCALBACK, RUNNING) interface. If no configured interface is found, fall back to the IP address of the machines hostname. 6 or 6{interface} The same as \4 but for IPv6. b Insert the baudrate of the current line. d Insert the current date. e or e{name} Translate the human-readable name to an escape sequence and insert it (for example: \e{red}Alert text.\e{reset}). If the name argument is not specified, then insert \033. The currently supported names are: black, blink, blue, bold, brown, cyan, darkgray, gray, green, halfbright, lightblue, lightcyan, lightgray, lightgreen, lightmagenta, lightred, magenta, red, reset, reverse, yellow and white. All unknown names are silently ignored. s Insert the system name (the name of the operating system). Same as 'uname -s'. See also the \S escape code. S or S{VARIABLE} Insert the VARIABLE data from /etc/os-release. If this file does not exist then fall back to /usr/lib/os-release. If the VARIABLE argument is not specified, then use PRETTY_NAME from the file or the system name (see \s). This escape code can be used to keep /etc/issue distribution and release independent. Note that \S{ANSI_COLOR} is converted to the real terminal escape sequence. l Insert the name of the current tty line. m Insert the architecture identifier of the machine. Same as uname -m. n Insert the nodename of the machine, also known as the hostname. Same as uname -n. o Insert the NIS domainname of the machine. Same as hostname -d. O Insert the DNS domainname of the machine. r Insert the release number of the OS. Same as uname -r. t Insert the current time. u Insert the number of current users logged in. U Insert the string "1 user" or "<n> users" where <n> is the number of current users logged in. v Insert the version of the OS, that is, the build-date and such. An example. On my system, the following /etc/issue file: This is \n.\o (\s \m \r) \t displays as: This is thingol.orcan.dk (Linux i386 1.1.9) 18:29:30 FILES top /var/run/utmp the system status file. /etc/issue printed before the login prompt. /etc/os-release /usr/lib/os-release operating system identification data. /dev/console problem reports (if syslog(3) is not used). /etc/inittab init(8) configuration file for SysV-style init daemon. CREDENTIALS top agetty supports configuration via systemd credentials (see https://systemd.io/CREDENTIALS/). agetty reads the following systemd credentials: agetty.autologin (string) If set, configures agetty to automatically log in the specified user without asking for a username or password, similarly to the --autologin option. BUGS top The baud-rate detection feature (the --extract-baud option) requires that agetty be scheduled soon enough after completion of a dial-in call (within 30 ms with modems that talk at 2400 baud). For robustness, always use the --extract-baud option in combination with a multiple baud rate command-line argument, so that BREAK processing is enabled. The text in the /etc/issue file (or other) and the login prompt are always output with 7-bit characters and space parity. The baud-rate detection feature (the --extract-baud option) requires that the modem emits its status message after raising the DCD line. DIAGNOSTICS top Depending on how the program was configured, all diagnostics are written to the console device or reported via the syslog(3) facility. Error messages are produced if the port argument does not specify a terminal device; if there is no utmp entry for the current process (System V only); and so on. AUTHORS top Werner Fink <werner@suse.de>, Karel Zak <kzak@redhat.com> The original agetty for serial terminals was written by W.Z. Venema <wietse@wzv.win.tue.nl> and ported to Linux by Peter Orbaek <poe@daimi.aau.dk>. REPORTING BUGS top For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues. AVAILABILITY top The agetty command is part of the util-linux package which can be downloaded from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>. This page is part of the util-linux (a random collection of Linux utilities) project. Information about the project can be found at https://www.kernel.org/pub/linux/utils/util-linux/. If you have a bug report for this manual page, send it to util-linux@vger.kernel.org. This page was obtained from the project's upstream Git repository git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git on 2023-12-22. (At that time, the date of the most recent commit that was found in the repository was 2023-12-14.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org util-linux 2.39.594-1e0ad 2023-07-19 AGETTY(8) Pages that refer to this page: tty(4), ttyS(4), issue(5), systemd.exec(5), ttytype(5), utmp(5), systemd.system-credentials(7), systemd-getty-generator(8) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # agetty\n\n> Alternative `getty`: Open a `tty` port, prompt for a login name, and invoke the `/bin/login` command.\n> It is normally invoked by `init`.\n> Note: the baud rate is the speed of data transfer between a terminal and a device over a serial connection.\n> More information: <https://manned.org/agetty>.\n\n- Connect `stdin` to a port (relative to `/dev`) and optionally specify a baud rate (defaults to 9600):\n\n`agetty {{tty}} {{115200}}`\n\n- Assume `stdin` is already connected to a `tty` and set a [t]imeout for the login:\n\n`agetty {{-t|--timeout}} {{timeout_in_seconds}} -`\n\n- Assume the `tty` is [8]-bit, overriding the `TERM` environment variable set by `init`:\n\n`agetty -8 - {{term_var}}`\n\n- Skip the login ([n]o login) and invoke, as root, another [l]ogin program instead of `/bin/login`:\n\n`agetty {{-n|--skip-login}} {{-l|--login-program}} {{login_program}} {{tty}}`\n\n- Do not display the pre-login ([i]ssue) file (`/etc/issue` by default) before writing the login prompt:\n\n`agetty {{-i|--noissue}} -`\n\n- Change the [r]oot directory and write a specific fake [H]ost into the `utmp` file:\n\n`agetty {{-r|--chroot}} {{/path/to/root_directory}} {{-H|--host}} {{fake_host}} -`\n |
alias | alias(1p) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training alias(1p) Linux manual page PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT ALIAS(1P) POSIX Programmer's Manual ALIAS(1P) PROLOG top This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME top alias define or display aliases SYNOPSIS top alias [alias-name[=string]...] DESCRIPTION top The alias utility shall create or redefine alias definitions or write the values of existing alias definitions to standard output. An alias definition provides a string value that shall replace a command name when it is encountered; see Section 2.3.1, Alias Substitution. An alias definition shall affect the current shell execution environment and the execution environments of the subshells of the current shell. When used as specified by this volume of POSIX.12017, the alias definition shall not affect the parent process of the current shell nor any utility environment invoked by the shell; see Section 2.12, Shell Execution Environment. OPTIONS top None. OPERANDS top The following operands shall be supported: alias-name Write the alias definition to standard output. alias-name=string Assign the value of string to the alias alias-name. If no operands are given, all alias definitions shall be written to standard output. STDIN top Not used. INPUT FILES top None. ENVIRONMENT VARIABLES top The following environment variables shall affect the execution of alias: LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.12017, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables. LC_CTYPE Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments). LC_MESSAGES Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error. NLSPATH Determine the location of message catalogs for the processing of LC_MESSAGES. ASYNCHRONOUS EVENTS top Default. STDOUT top The format for displaying aliases (when no operands or only name operands are specified) shall be: "%s=%s\n", name, value The value string shall be written with appropriate quoting so that it is suitable for reinput to the shell. See the description of shell quoting in Section 2.2, Quoting. STDERR top The standard error shall be used only for diagnostic messages. OUTPUT FILES top None. EXTENDED DESCRIPTION top None. EXIT STATUS top The following exit values shall be returned: 0 Successful completion. >0 One of the name operands specified did not have an alias definition, or an error occurred. CONSEQUENCES OF ERRORS top Default. The following sections are informative. APPLICATION USAGE top None. EXAMPLES top 1. Create a short alias for a commonly used ls command: alias lf="ls -CF" 2. Create a simple ``redo'' command to repeat previous entries in the command history file: alias r='fc -s' 3. Use 1K units for du: alias du=du\ -k 4. Set up nohup so that it can deal with an argument that is itself an alias name: alias nohup="nohup " RATIONALE top The alias description is based on historical KornShell implementations. Known differences exist between that and the C shell. The KornShell version was adopted to be consistent with all the other KornShell features in this volume of POSIX.12017, such as command line editing. Since alias affects the current shell execution environment, it is generally provided as a shell regular built-in. Historical versions of the KornShell have allowed aliases to be exported to scripts that are invoked by the same shell. This is triggered by the alias -x flag; it is allowed by this volume of POSIX.12017 only when an explicit extension such as -x is used. The standard developers considered that aliases were of use primarily to interactive users and that they should normally not affect shell scripts called by those users; functions are available to such scripts. Historical versions of the KornShell had not written aliases in a quoted manner suitable for reentry to the shell, but this volume of POSIX.12017 has made this a requirement for all similar output. Therefore, consistency was chosen over this detail of historical practice. FUTURE DIRECTIONS top None. SEE ALSO top Section 2.9.5, Function Definition Command The Base Definitions volume of POSIX.12017, Chapter 8, Environment Variables COPYRIGHT top Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . IEEE/The Open Group 2017 ALIAS(1P) Pages that refer to this page: unalias(1p) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # alias\n\n> Creates aliases -- words that are replaced by a command string.\n> Aliases expire with the current shell session unless defined in the shell's configuration file, e.g. `~/.bashrc`.\n> More information: <https://tldp.org/LDP/abs/html/aliases.html>.\n\n- List all aliases:\n\n`alias`\n\n- Create a generic alias:\n\n`alias {{word}}="{{command}}"`\n\n- View the command associated to a given alias:\n\n`alias {{word}}`\n\n- Remove an aliased command:\n\n`unalias {{word}}`\n\n- Turn `rm` into an interactive command:\n\n`alias {{rm}}="{{rm --interactive}}"`\n\n- Create `la` as a shortcut for `ls --all`:\n\n`alias {{la}}="{{ls --all}}"`\n |
apropos | apropos(1) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training apropos(1) Linux manual page NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXIT STATUS | ENVIRONMENT | FILES | SEE ALSO | AUTHOR | BUGS | COLOPHON APROPOS(1) Manual pager utils APROPOS(1) NAME top apropos - search the manual page names and descriptions SYNOPSIS top apropos [-dalv?V] [-e|-w|-r] [-s list] [-m system[,...]] [-M path] [-L locale] [-C file] keyword ... DESCRIPTION top Each manual page has a short description available within it. apropos searches the descriptions for instances of keyword. keyword is usually a regular expression, as if (-r) was used, or may contain wildcards (-w), or match the exact keyword (-e). Using these options, it may be necessary to quote the keyword or escape (\) the special characters to stop the shell from interpreting them. The standard matching rules allow matches to be made against the page name and word boundaries in the description. The database searched by apropos is updated by the mandb program. Depending on your installation, this may be run by a periodic cron job, or may need to be run manually after new manual pages have been installed. OPTIONS top -d, --debug Print debugging information. -v, --verbose Print verbose warning messages. -r, --regex Interpret each keyword as a regular expression. This is the default behaviour. Each keyword will be matched against the page names and the descriptions independently. It can match any part of either. The match is not limited to word boundaries. -w, --wildcard Interpret each keyword as a pattern containing shell style wildcards. Each keyword will be matched against the page names and the descriptions independently. If --exact is also used, a match will only be found if an expanded keyword matches an entire description or page name. Otherwise the keyword is also allowed to match on word boundaries in the description. -e, --exact Each keyword will be exactly matched against the page names and the descriptions. -a, --and Only display items that match all the supplied keywords. The default is to display items that match any keyword. -l, --long Do not trim output to the terminal width. Normally, output will be truncated to the terminal width to avoid ugly results from poorly-written NAME sections. -s list, --sections=list, --section=list Search only the given manual sections. list is a colon- or comma-separated list of sections. If an entry in list is a simple section, for example "3", then the displayed list of descriptions will include pages in sections "3", "3perl", "3x", and so on; while if an entry in list has an extension, for example "3perl", then the list will only include pages in that exact part of the manual section. -m system[,...], --systems=system[,...] If this system has access to other operating systems' manual page descriptions, they can be searched using this option. To search NewOS's manual page descriptions, use the option -m NewOS. The system specified can be a combination of comma- delimited operating system names. To include a search of the native operating system's whatis descriptions, include the system name man in the argument string. This option will override the $SYSTEM environment variable. -M path, --manpath=path Specify an alternate set of colon-delimited manual page hierarchies to search. By default, apropos uses the $MANPATH environment variable, unless it is empty or unset, in which case it will determine an appropriate manpath based on your $PATH environment variable. This option overrides the contents of $MANPATH. -L locale, --locale=locale apropos will normally determine your current locale by a call to the C function setlocale(3) which interrogates various environment variables, possibly including $LC_MESSAGES and $LANG. To temporarily override the determined value, use this option to supply a locale string directly to apropos. Note that it will not take effect until the search for pages actually begins. Output such as the help message will always be displayed in the initially determined locale. -C file, --config-file=file Use this user configuration file rather than the default of ~/.manpath. -?, --help Print a help message and exit. --usage Print a short usage message and exit. -V, --version Display version information. EXIT STATUS top 0 Successful program execution. 1 Usage, syntax or configuration file error. 2 Operational error. 16 Nothing was found that matched the criteria specified. ENVIRONMENT top SYSTEM If $SYSTEM is set, it will have the same effect as if it had been specified as the argument to the -m option. MANPATH If $MANPATH is set, its value is interpreted as the colon- delimited manual page hierarchy search path to use. See the SEARCH PATH section of manpath(5) for the default behaviour and details of how this environment variable is handled. MANWIDTH If $MANWIDTH is set, its value is used as the terminal width (see the --long option). If it is not set, the terminal width will be calculated using the value of $COLUMNS, and ioctl(2) if available, or falling back to 80 characters if all else fails. POSIXLY_CORRECT If $POSIXLY_CORRECT is set, even to a null value, the default apropos search will be as an extended regex (-r). Nowadays, this is the default behaviour anyway. FILES top /usr/share/man/index.(bt|db|dir|pag) A traditional global index database cache. /var/cache/man/index.(bt|db|dir|pag) An FHS compliant global index database cache. /usr/share/man/.../whatis A traditional whatis text database. SEE ALSO top man(1), whatis(1), mandb(8) AUTHOR top Wilf. (G.Wilford@ee.surrey.ac.uk). Fabrizio Polacco (fpolacco@debian.org). Colin Watson (cjwatson@debian.org). BUGS top https://gitlab.com/man-db/man-db/-/issues https://savannah.nongnu.org/bugs/?group=man-db COLOPHON top This page is part of the man-db (manual pager suite) project. Information about the project can be found at http://www.nongnu.org/man-db/. If you have a bug report for this manual page, send it to man-db-devel@nongnu.org. This page was obtained from the project's upstream Git repository https://gitlab.com/cjwatson/man-db on 2023-12-22. (At that time, the date of the most recent commit that was found in the repository was 2023-12-18.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org 2.12.0 2023-09-23 APROPOS(1) Pages that refer to this page: lexgrog(1), man(1), manpath(1), whatis(1), man(7) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # apropos\n\n> Search the manual pages for names and descriptions.\n> More information: <https://manned.org/apropos>.\n\n- Search for a keyword using a regular expression:\n\n`apropos {{regular_expression}}`\n\n- Search without restricting the output to the terminal width ([l]ong output):\n\n`apropos -l {{regular_expression}}`\n\n- Search for pages that match [a]ll the expressions given:\n\n`apropos {{regular_expression_1}} -a {{regular_expression_2}} -a {{regular_expression_3}}`\n |
ar | ar(1) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training ar(1) Linux manual page NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT | COLOPHON AR(1) GNU Development Tools AR(1) NAME top ar - create, modify, and extract from archives SYNOPSIS top ar [-X32_64] [-]p[mod] [--plugin name] [--target bfdname] [--output dirname] [--record-libdeps libdeps] [--thin] [relpos] [count] archive [member...] DESCRIPTION top The GNU ar program creates, modifies, and extracts from archives. An archive is a single file holding a collection of other files in a structure that makes it possible to retrieve the original individual files (called members of the archive). The original files' contents, mode (permissions), timestamp, owner, and group are preserved in the archive, and can be restored on extraction. GNU ar can maintain archives whose members have names of any length; however, depending on how ar is configured on your system, a limit on member-name length may be imposed for compatibility with archive formats maintained with other tools. If it exists, the limit is often 15 characters (typical of formats related to a.out) or 16 characters (typical of formats related to coff). ar is considered a binary utility because archives of this sort are most often used as libraries holding commonly needed subroutines. Since libraries often will depend on other libraries, ar can also record the dependencies of a library when the --record-libdeps option is specified. ar creates an index to the symbols defined in relocatable object modules in the archive when you specify the modifier s. Once created, this index is updated in the archive whenever ar makes a change to its contents (save for the q update operation). An archive with such an index speeds up linking to the library, and allows routines in the library to call each other without regard to their placement in the archive. You may use nm -s or nm --print-armap to list this index table. If an archive lacks the table, another form of ar called ranlib can be used to add just the table. GNU ar can optionally create a thin archive, which contains a symbol index and references to the original copies of the member files of the archive. This is useful for building libraries for use within a local build tree, where the relocatable objects are expected to remain available, and copying the contents of each object would only waste time and space. An archive can either be thin or it can be normal. It cannot be both at the same time. Once an archive is created its format cannot be changed without first deleting it and then creating a new archive in its place. Thin archives are also flattened, so that adding one thin archive to another thin archive does not nest it, as would happen with a normal archive. Instead the elements of the first archive are added individually to the second archive. The paths to the elements of the archive are stored relative to the archive itself. GNU ar is designed to be compatible with two different facilities. You can control its activity using command-line options, like the different varieties of ar on Unix systems; or, if you specify the single command-line option -M, you can control it with a script supplied via standard input, like the MRI "librarian" program. OPTIONS top GNU ar allows you to mix the operation code p and modifier flags mod in any order, within the first command-line argument. If you wish, you may begin the first command-line argument with a dash. The p keyletter specifies what operation to execute; it may be any of the following, but you must specify only one of them: d Delete modules from the archive. Specify the names of modules to be deleted as member...; the archive is untouched if you specify no files to delete. If you specify the v modifier, ar lists each module as it is deleted. m Use this operation to move members in an archive. The ordering of members in an archive can make a difference in how programs are linked using the library, if a symbol is defined in more than one member. If no modifiers are used with "m", any members you name in the member arguments are moved to the end of the archive; you can use the a, b, or i modifiers to move them to a specified place instead. p Print the specified members of the archive, to the standard output file. If the v modifier is specified, show the member name before copying its contents to standard output. If you specify no member arguments, all the files in the archive are printed. q Quick append; Historically, add the files member... to the end of archive, without checking for replacement. The modifiers a, b, and i do not affect this operation; new members are always placed at the end of the archive. The modifier v makes ar list each file as it is appended. Since the point of this operation is speed, implementations of ar have the option of not updating the archive's symbol table if one exists. Too many different systems however assume that symbol tables are always up-to-date, so GNU ar will rebuild the table even with a quick append. Note - GNU ar treats the command qs as a synonym for r - replacing already existing files in the archive and appending new ones at the end. r Insert the files member... into archive (with replacement). This operation differs from q in that any previously existing members are deleted if their names match those being added. If one of the files named in member... does not exist, ar displays an error message, and leaves undisturbed any existing members of the archive matching that name. By default, new members are added at the end of the file; but you may use one of the modifiers a, b, or i to request placement relative to some existing member. The modifier v used with this operation elicits a line of output for each file inserted, along with one of the letters a or r to indicate whether the file was appended (no old member deleted) or replaced. s Add an index to the archive, or update it if it already exists. Note this command is an exception to the rule that there can only be one command letter, as it is possible to use it as either a command or a modifier. In either case it does the same thing. t Display a table listing the contents of archive, or those of the files listed in member... that are present in the archive. Normally only the member name is shown, but if the modifier O is specified, then the corresponding offset of the member is also displayed. Finally, in order to see the modes (permissions), timestamp, owner, group, and size the v modifier should be included. If you do not specify a member, all files in the archive are listed. If there is more than one file with the same name (say, fie) in an archive (say b.a), ar t b.a fie lists only the first instance; to see them all, you must ask for a complete listing---in our example, ar t b.a. x Extract members (named member) from the archive. You can use the v modifier with this operation, to request that ar list each name as it extracts it. If you do not specify a member, all files in the archive are extracted. Files cannot be extracted from a thin archive, and there are restrictions on extracting from archives created with P: The paths must not be absolute, may not contain "..", and any subdirectories in the paths must exist. If it is desired to avoid these restrictions then used the --output option to specify an output directory. A number of modifiers (mod) may immediately follow the p keyletter, to specify variations on an operation's behavior: a Add new files after an existing member of the archive. If you use the modifier a, the name of an existing archive member must be present as the relpos argument, before the archive specification. b Add new files before an existing member of the archive. If you use the modifier b, the name of an existing archive member must be present as the relpos argument, before the archive specification. (same as i). c Create the archive. The specified archive is always created if it did not exist, when you request an update. But a warning is issued unless you specify in advance that you expect to create it, by using this modifier. D Operate in deterministic mode. When adding files and the archive index use zero for UIDs, GIDs, timestamps, and use consistent file modes for all files. When this option is used, if ar is used with identical options and identical input files, multiple runs will create identical output files regardless of the input files' owners, groups, file modes, or modification times. If binutils was configured with --enable-deterministic-archives, then this mode is on by default. It can be disabled with the U modifier, below. f Truncate names in the archive. GNU ar will normally permit file names of any length. This will cause it to create archives which are not compatible with the native ar program on some systems. If this is a concern, the f modifier may be used to truncate file names when putting them in the archive. i Insert new files before an existing member of the archive. If you use the modifier i, the name of an existing archive member must be present as the relpos argument, before the archive specification. (same as b). l Specify dependencies of this library. The dependencies must immediately follow this option character, must use the same syntax as the linker command line, and must be specified within a single argument. I.e., if multiple items are needed, they must be quoted to form a single command line argument. For example L "-L/usr/local/lib -lmydep1 -lmydep2" N Uses the count parameter. This is used if there are multiple entries in the archive with the same name. Extract or delete instance count of the given name from the archive. o Preserve the original dates of members when extracting them. If you do not specify this modifier, files extracted from the archive are stamped with the time of extraction. O Display member offsets inside the archive. Use together with the t option. P Use the full path name when matching or storing names in the archive. Archives created with full path names are not POSIX compliant, and thus may not work with tools other than up to date GNU tools. Modifying such archives with GNU ar without using P will remove the full path names unless the archive is a thin archive. Note that P may be useful when adding files to a thin archive since r without P ignores the path when choosing which element to replace. Thus ar rcST archive.a subdir/file1 subdir/file2 file1 will result in the first "subdir/file1" being replaced with "file1" from the current directory. Adding P will prevent this replacement. s Write an object-file index into the archive, or update an existing one, even if no other change is made to the archive. You may use this modifier flag either with any operation, or alone. Running ar s on an archive is equivalent to running ranlib on it. S Do not generate an archive symbol table. This can speed up building a large library in several steps. The resulting archive can not be used with the linker. In order to build a symbol table, you must omit the S modifier on the last execution of ar, or you must run ranlib on the archive. T Deprecated alias for --thin. T is not recommended because in many ar implementations T has a different meaning, as specified by X/Open System Interface. u Normally, ar r... inserts all files listed into the archive. If you would like to insert only those of the files you list that are newer than existing members of the same names, use this modifier. The u modifier is allowed only for the operation r (replace). In particular, the combination qu is not allowed, since checking the timestamps would lose any speed advantage from the operation q. U Do not operate in deterministic mode. This is the inverse of the D modifier, above: added files and the archive index will get their actual UID, GID, timestamp, and file mode values. This is the default unless binutils was configured with --enable-deterministic-archives. v This modifier requests the verbose version of an operation. Many operations display additional information, such as filenames processed, when the modifier v is appended. V This modifier shows the version number of ar. The ar program also supports some command-line options which are neither modifiers nor actions, but which do change its behaviour in specific ways: --help Displays the list of command-line options supported by ar and then exits. --version Displays the version information of ar and then exits. -X32_64 ar ignores an initial option spelled -X32_64, for compatibility with AIX. The behaviour produced by this option is the default for GNU ar. ar does not support any of the other -X options; in particular, it does not support -X32 which is the default for AIX ar. --plugin name The optional command-line switch --plugin name causes ar to load the plugin called name which adds support for more file formats, including object files with link-time optimization information. This option is only available if the toolchain has been built with plugin support enabled. If --plugin is not provided, but plugin support has been enabled then ar iterates over the files in ${libdir}/bfd-plugins in alphabetic order and the first plugin that claims the object in question is used. Please note that this plugin search directory is not the one used by ld's -plugin option. In order to make ar use the linker plugin it must be copied into the ${libdir}/bfd-plugins directory. For GCC based compilations the linker plugin is called liblto_plugin.so.0.0.0. For Clang based compilations it is called LLVMgold.so. The GCC plugin is always backwards compatible with earlier versions, so it is sufficient to just copy the newest one. --target target The optional command-line switch --target bfdname specifies that the archive members are in an object code format different from your system's default format. See --output dirname The --output option can be used to specify a path to a directory into which archive members should be extracted. If this option is not specified then the current directory will be used. Note - although the presence of this option does imply a x extraction operation that option must still be included on the command line. --record-libdeps libdeps The --record-libdeps option is identical to the l modifier, just handled in long form. --thin Make the specified archive a thin archive. If it already exists and is a regular archive, the existing members must be present in the same directory as archive. @file Read command-line options from file. The options read are inserted in place of the original @file option. If file does not exist, or cannot be read, then the option will be treated literally, and not removed. Options in file are separated by whitespace. A whitespace character may be included in an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) may be included by prefixing the character to be included with a backslash. The file may itself contain additional @file options; any such options will be processed recursively. SEE ALSO top nm(1), ranlib(1), and the Info entries for binutils. COPYRIGHT top Copyright (c) 1991-2023 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". COLOPHON top This page is part of the binutils (a collection of tools for working with executable binaries) project. Information about the project can be found at http://www.gnu.org/software/binutils/. If you have a bug report for this manual page, see http://sourceware.org/bugzilla/enter_bug.cgi?product=binutils. This page was obtained from the tarball binutils-2.41.tar.gz fetched from https://ftp.gnu.org/gnu/binutils/ on 2023-12-22. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org binutils-2.41 2023-12-22 AR(1) Pages that refer to this page: ld(1), nm(1), ranlib(1), size(1), strings(1), uselib(2) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # ar\n\n> Create, modify, and extract from Unix archives. Typically used for static libraries (`.a`) and Debian packages (`.deb`).\n> See also: `tar`.\n> More information: <https://manned.org/ar>.\n\n- E[x]tract all members from an archive:\n\n`ar x {{path/to/file.a}}`\n\n- Lis[t] contents in a specific archive:\n\n`ar t {{path/to/file.ar}}`\n\n- [r]eplace or add specific files to an archive:\n\n`ar r {{path/to/file.deb}} {{path/to/debian-binary path/to/control.tar.gz path/to/data.tar.xz ...}}`\n\n- In[s]ert an object file index (equivalent to using `ranlib`):\n\n`ar s {{path/to/file.a}}`\n\n- Create an archive with specific files and an accompanying object file index:\n\n`ar rs {{path/to/file.a}} {{path/to/file1.o path/to/file2.o ...}}`\n |
arch | arch(1) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training arch(1) Linux manual page NAME | SYNOPSIS | DESCRIPTION | AUTHOR | REPORTING BUGS | COPYRIGHT | SEE ALSO | COLOPHON ARCH(1) User Commands ARCH(1) NAME top arch - print machine hardware name (same as uname -m) SYNOPSIS top arch [OPTION]... DESCRIPTION top Print machine architecture. --help display this help and exit --version output version information and exit AUTHOR top Written by David MacKenzie and Karel Zak. REPORTING BUGS top GNU coreutils online help: <https://www.gnu.org/software/coreutils/> Report any translation bugs to <https://translationproject.org/team/> COPYRIGHT top Copyright 2023 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. SEE ALSO top uname(1), uname(2) Full documentation <https://www.gnu.org/software/coreutils/arch> or available locally via: info '(coreutils) arch invocation' COLOPHON top This page is part of the coreutils (basic file, shell and text manipulation utilities) project. Information about the project can be found at http://www.gnu.org/software/coreutils/. If you have a bug report for this manual page, see http://www.gnu.org/software/coreutils/. This page was obtained from the tarball coreutils-9.4.tar.xz fetched from http://ftp.gnu.org/gnu/coreutils/ on 2023-12-22. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org GNU coreutils 9.4 August 2023 ARCH(1) Pages that refer to this page: uname(1) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # arch\n\n> Display the name of the system architecture.\n> See also `uname`.\n> More information: <https://www.gnu.org/software/coreutils/arch>.\n\n- Display the system's architecture:\n\n`arch`\n |
arp | arp(8) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training arp(8) Linux manual page NAME | SYNOPSIS | DESCRIPTION | MODES | OPTIONS | EXAMPLES | FILES | SEE ALSO | AUTHORS | COLOPHON ARP(8) Linux System Administrator's Manual ARP(8) NAME top arp - manipulate the system ARP cache SYNOPSIS top arp [-vn] [-H type] [-i if] [-ae] [hostname] arp [-v] [-i if] -d hostname [pub] arp [-v] [-H type] [-i if] -s hostname hw_addr [temp] arp [-v] [-H type] [-i if] -s hostname hw_addr [netmask nm] pub arp [-v] [-H type] [-i if] -Ds hostname ifname [netmask nm] pub arp [-vnD] [-H type] [-i if] -f [filename] DESCRIPTION top Arp manipulates or displays the kernel's IPv4 network neighbour cache. It can add entries to the table, delete one or display the current content. ARP stands for Address Resolution Protocol, which is used to find the media access control address of a network neighbour for a given IPv4 Address. MODES top arp with no mode specifier will print the current content of the table. It is possible to limit the number of entries printed, by specifying an hardware address type, interface name or host address. arp -d address will delete a ARP table entry. Root or netadmin privilege is required to do this. The entry is found by IP address. If a hostname is given, it will be resolved before looking up the entry in the ARP table. arp -s address hw_addr is used to set up a new table entry. The format of the hw_addr parameter is dependent on the hardware class, but for most classes one can assume that the usual presentation can be used. For the Ethernet class, this is 6 bytes in hexadecimal, separated by colons. When adding proxy arp entries (that is those with the publish flag set) a netmask may be specified to proxy arp for entire subnets. This is not good practice, but is supported by older kernels because it can be useful. If the temp flag is not supplied entries will be permanent stored into the ARP cache. To simplify setting up entries for one of your own network interfaces, you can use the arp -Ds address ifname form. In that case the hardware address is taken from the interface with the specified name. OPTIONS top -v, --verbose Tell the user what is going on by being verbose. -n, --numeric shows numerical addresses instead of trying to determine symbolic host, port or user names. -H type, --hw-type type, -t type When setting or reading the ARP cache, this optional parameter tells arp which class of entries it should check for. The default value of this parameter is ether (i.e. hardware code 0x01 for IEEE 802.3 10Mbps Ethernet). Other values might include network technologies such as ARCnet (arcnet) , PROnet (pronet) , AX.25 (ax25) and NET/ROM (netrom). -a Use alternate BSD style output format (with no fixed columns). -e Use default Linux style output format (with fixed columns). -D, --use-device Instead of a hw_addr, the given argument is the name of an interface. arp will use the MAC address of that interface for the table entry. This is usually the best option to set up a proxy ARP entry to yourself. -i If, --device If Select an interface. When dumping the ARP cache only entries matching the specified interface will be printed. When setting a permanent or temp ARP entry this interface will be associated with the entry; if this option is not used, the kernel will guess based on the routing table. For pub entries the specified interface is the interface on which ARP requests will be answered. NOTE: This has to be different from the interface to which the IP datagrams will be routed. NOTE: As of kernel 2.2.0 it is no longer possible to set an ARP entry for an entire subnet. Linux instead does automagic proxy arp when a route exists and it is forwarding. See arp(7) for details. Also the dontpub option which is available for delete and set operations cannot be used with 2.4 and newer kernels. -f filename, --file filename Similar to the -s option, only this time the address info is taken from file filename. This can be used if ARP entries for a lot of hosts have to be set up. The name of the data file is very often /etc/ethers, but this is not official. If no filename is specified /etc/ethers is used as default. The format of the file is simple; it only contains ASCII text lines with a hostname, and a hardware address separated by whitespace. Additionally the pub, temp and netmask flags can be used. In all places where a hostname is expected, one can also enter an IP address in dotted-decimal notation. As a special case for compatibility the order of the hostname and the hardware address can be exchanged. Each complete entry in the ARP cache will be marked with the C flag. Permanent entries are marked with M and published entries have the P flag. EXAMPLES top /usr/sbin/arp -i eth0 -Ds 10.0.0.2 eth1 pub This will answer ARP requests for 10.0.0.2 on eth0 with the MAC address for eth1. /usr/sbin/arp -i eth1 -d 10.0.0.1 Delete the ARP table entry for 10.0.0.1 on interface eth1. This will match published proxy ARP entries and permanent entries. FILES top /proc/net/arp /etc/networks /etc/hosts /etc/ethers SEE ALSO top ethers(5), rarp(8), route(8), ifconfig(8), netstat(8) AUTHORS top Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>, Bernd Eckenfels <net-tools@lina.inka.de>. COLOPHON top This page is part of the net-tools (networking utilities) project. Information about the project can be found at http://net-tools.sourceforge.net/. If you have a bug report for this manual page, see http://net-tools.sourceforge.net/. This page was obtained from the project's upstream Git repository git://git.code.sf.net/p/net-tools/code on 2023-12-22. (At that time, the date of the most recent commit that was found in the repository was 2023-06-29.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org net-tools 2008-10-03 ARP(8) Pages that refer to this page: ethers(5), proc(5), ifconfig(8), rarp(8), route(8) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # arp\n\n> Show and manipulate your system's ARP cache.\n> More information: <https://manned.org/arp>.\n\n- Show the current ARP table:\n\n`arp -a`\n\n- [d]elete a specific entry:\n\n`arp -d {{address}}`\n\n- [s]et up a new entry in the ARP table:\n\n`arp -s {{address}} {{mac_address}}`\n |
arping | arping(8) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training arping(8) Linux manual page NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SEE ALSO | AUTHOR | SECURITY | AVAILABILITY | COLOPHON ARPING(8) iputils ARPING(8) NAME top arping - send ARP REQUEST to a neighbour host SYNOPSIS top arping [-AbDfhqUV] [-c count] [-w deadline] [-i interval] [-s source] [-I interface] {destination} DESCRIPTION top Ping destination on device interface by ARP packets, using source address source. arping supports IPv4 addresses only. For IPv6, see ndisc6(8). OPTIONS top -A The same as -U, but ARP REPLY packets used instead of ARP REQUEST. -b Send only MAC level broadcasts. Normally arping starts from sending broadcast, and switch to unicast after reply received. -c count Stop after sending count ARP REQUEST packets. With deadline option, instead wait for count ARP REPLY packets, or until the timeout expires. -D Duplicate address detection mode (DAD). See RFC2131, 4.4.1. Returns 0, if DAD succeeded i.e. no replies are received. -f Finish after the first reply confirming that target is alive. -I interface Name of network device where to send ARP REQUEST packets. -h Print help page and exit. -q Quiet output. Nothing is displayed. -s source IP source address to use in ARP packets. If this option is absent, source address is: In DAD mode (with option -D) set to 0.0.0.0. In Unsolicited ARP mode (with options -U or -A) set to destination. Otherwise, it is calculated from routing tables. -U Unsolicited ARP mode to update neighbours' ARP caches. No replies are expected. -V Print version of the program and exit. -w deadline Specify a timeout, in seconds, before arping exits regardless of how many packets have been sent or received. If any replies are received, exit with status 0, otherwise status 1. When combined with the count option, exit with status 0 if count replies are received before the deadline expiration, otherwise status 1. -i interval Specify an interval, in seconds, between packets. SEE ALSO top ndisc6(8), ping(8), clockdiff(8), tracepath(8). AUTHOR top arping was written by Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>. SECURITY top arping requires CAP_NET_RAW capability to be executed. It is not recommended to be used as set-uid root, because it allows user to modify ARP caches of neighbour hosts. AVAILABILITY top arping is part of iputils package. COLOPHON top This page is part of the iputils (IP utilities) project. Information about the project can be found at http://www.skbuff.net/iputils/. If you have a bug report for this manual page, send it to yoshfuji@skbuff.net, netdev@vger.kernel.org. This page was obtained from the project's upstream Git repository https://github.com/iputils/iputils.git on 2023-12-22. (At that time, the date of the most recent commit that was found in the repository was 2023-12-22.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org iputils 20221126 ARPING(8) Pages that refer to this page: clockdiff(8) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # arping\n\n> Discover and probe hosts in a network using the ARP protocol.\n> Useful for MAC address discovery.\n> More information: <https://github.com/ThomasHabets/arping>.\n\n- Ping a host by ARP request packets:\n\n`arping {{host_ip}}`\n\n- Ping a host on a specific interface:\n\n`arping -I {{interface}} {{host_ip}}`\n\n- Ping a host and [f]inish after the first reply:\n\n`arping -f {{host_ip}}`\n\n- Ping a host a specific number ([c]ount) of times:\n\n`arping -c {{count}} {{host_ip}}`\n\n- Broadcast ARP request packets to update neighbours' ARP caches ([U]nsolicited ARP mode):\n\n`arping -U {{ip_to_broadcast}}`\n\n- [D]etect duplicated IP addresses in the network by sending ARP requests with a 3 second timeout:\n\n`arping -D -w {{3}} {{ip_to_check}}`\n |
as | as(1) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training as(1) Linux manual page NAME | SYNOPSIS | TARGET | DESCRIPTION | OPTIONS | SEE ALSO | COPYRIGHT | COLOPHON AS(1) GNU Development Tools AS(1) NAME top AS - the portable GNU assembler. SYNOPSIS top as [-a[cdghlns][=file]] [--alternate] [--compress-debug-sections] [--nocompress-debug-sections] [-D] [--dump-config] [--debug-prefix-map old=new] [--defsym sym=val] [--elf-stt-common=[no|yes]] [--emulation=name] [-f] [-g] [--gstabs] [--gstabs+] [--gdwarf-<N>] [--gdwarf-sections] [--gdwarf-cie-version=VERSION] [--generate-missing-build-notes=[no|yes]] [--gsframe] [--hash-size=N] [--help] [--target-help] [-I dir] [-J] [-K] [--keep-locals] [-L] [--listing-lhs-width=NUM] [--listing-lhs-width2=NUM] [--listing-rhs-width=NUM] [--listing-cont-lines=NUM] [--multibyte-handling=[allow|warn|warn-sym-only]] [--no-pad-sections] [-o objfile] [-R] [--sectname-subst] [--size-check=[error|warning]] [--statistics] [-v] [-version] [--version] [-W] [--warn] [--fatal-warnings] [-w] [-x] [-Z] [@FILE] [target-options] [--|files ...] TARGET top Target AArch64 options: [-EB|-EL] [-mabi=ABI] Target Alpha options: [-mcpu] [-mdebug | -no-mdebug] [-replace | -noreplace] [-relax] [-g] [-Gsize] [-F] [-32addr] Target ARC options: [-mcpu=cpu] [-mA6|-mARC600|-mARC601|-mA7|-mARC700|-mEM|-mHS] [-mcode-density] [-mrelax] [-EB|-EL] Target ARM options: [-mcpu=processor[+extension...]] [-march=architecture[+extension...]] [-mfpu=floating-point-format] [-mfloat-abi=abi] [-meabi=ver] [-mthumb] [-EB|-EL] [-mapcs-32|-mapcs-26|-mapcs-float| -mapcs-reentrant] [-mthumb-interwork] [-k] Target Blackfin options: [-mcpu=processor[-sirevision]] [-mfdpic] [-mno-fdpic] [-mnopic] Target BPF options: [-EL] [-EB] Target CRIS options: [--underscore | --no-underscore] [--pic] [-N] [--emulation=criself | --emulation=crisaout] [--march=v0_v10 | --march=v10 | --march=v32 | --march=common_v10_v32] Target C-SKY options: [-march=arch] [-mcpu=cpu] [-EL] [-mlittle-endian] [-EB] [-mbig-endian] [-fpic] [-pic] [-mljump] [-mno-ljump] [-force2bsr] [-mforce2bsr] [-no-force2bsr] [-mno-force2bsr] [-jsri2bsr] [-mjsri2bsr] [-no-jsri2bsr ] [-mno-jsri2bsr] [-mnolrw ] [-mno-lrw] [-melrw] [-mno-elrw] [-mlaf ] [-mliterals-after-func] [-mno-laf] [-mno-literals-after-func] [-mlabr] [-mliterals-after-br] [-mno-labr] [-mnoliterals-after-br] [-mistack] [-mno-istack] [-mhard-float] [-mmp] [-mcp] [-mcache] [-msecurity] [-mtrust] [-mdsp] [-medsp] [-mvdsp] Target D10V options: [-O] Target D30V options: [-O|-n|-N] Target EPIPHANY options: [-mepiphany|-mepiphany16] Target H8/300 options: [-h-tick-hex] Target i386 options: [--32|--x32|--64] [-n] [-march=CPU[+EXTENSION...]] [-mtune=CPU] Target IA-64 options: [-mconstant-gp|-mauto-pic] [-milp32|-milp64|-mlp64|-mp64] [-mle|mbe] [-mtune=itanium1|-mtune=itanium2] [-munwind-check=warning|-munwind-check=error] [-mhint.b=ok|-mhint.b=warning|-mhint.b=error] [-x|-xexplicit] [-xauto] [-xdebug] Target IP2K options: [-mip2022|-mip2022ext] Target M32C options: [-m32c|-m16c] [-relax] [-h-tick-hex] Target M32R options: [--m32rx|--[no-]warn-explicit-parallel-conflicts| --W[n]p] Target M680X0 options: [-l] [-m68000|-m68010|-m68020|...] Target M68HC11 options: [-m68hc11|-m68hc12|-m68hcs12|-mm9s12x|-mm9s12xg] [-mshort|-mlong] [-mshort-double|-mlong-double] [--force-long-branches] [--short-branches] [--strict-direct-mode] [--print-insn-syntax] [--print-opcodes] [--generate-example] Target MCORE options: [-jsri2bsr] [-sifilter] [-relax] [-mcpu=[210|340]] Target Meta options: [-mcpu=cpu] [-mfpu=cpu] [-mdsp=cpu] Target MICROBLAZE options: Target MIPS options: [-nocpp] [-EL] [-EB] [-O[optimization level]] [-g[debug level]] [-G num] [-KPIC] [-call_shared] [-non_shared] [-xgot [-mvxworks-pic] [-mabi=ABI] [-32] [-n32] [-64] [-mfp32] [-mgp32] [-mfp64] [-mgp64] [-mfpxx] [-modd-spreg] [-mno-odd-spreg] [-march=CPU] [-mtune=CPU] [-mips1] [-mips2] [-mips3] [-mips4] [-mips5] [-mips32] [-mips32r2] [-mips32r3] [-mips32r5] [-mips32r6] [-mips64] [-mips64r2] [-mips64r3] [-mips64r5] [-mips64r6] [-construct-floats] [-no-construct-floats] [-mignore-branch-isa] [-mno-ignore-branch-isa] [-mnan=encoding] [-trap] [-no-break] [-break] [-no-trap] [-mips16] [-no-mips16] [-mmips16e2] [-mno-mips16e2] [-mmicromips] [-mno-micromips] [-msmartmips] [-mno-smartmips] [-mips3d] [-no-mips3d] [-mdmx] [-no-mdmx] [-mdsp] [-mno-dsp] [-mdspr2] [-mno-dspr2] [-mdspr3] [-mno-dspr3] [-mmsa] [-mno-msa] [-mxpa] [-mno-xpa] [-mmt] [-mno-mt] [-mmcu] [-mno-mcu] [-mcrc] [-mno-crc] [-mginv] [-mno-ginv] [-mloongson-mmi] [-mno-loongson-mmi] [-mloongson-cam] [-mno-loongson-cam] [-mloongson-ext] [-mno-loongson-ext] [-mloongson-ext2] [-mno-loongson-ext2] [-minsn32] [-mno-insn32] [-mfix7000] [-mno-fix7000] [-mfix-rm7000] [-mno-fix-rm7000] [-mfix-vr4120] [-mno-fix-vr4120] [-mfix-vr4130] [-mno-fix-vr4130] [-mfix-r5900] [-mno-fix-r5900] [-mdebug] [-no-mdebug] [-mpdr] [-mno-pdr] Target MMIX options: [--fixed-special-register-names] [--globalize-symbols] [--gnu-syntax] [--relax] [--no-predefined-symbols] [--no-expand] [--no-merge-gregs] [-x] [--linker-allocated-gregs] Target Nios II options: [-relax-all] [-relax-section] [-no-relax] [-EB] [-EL] Target NDS32 options: [-EL] [-EB] [-O] [-Os] [-mcpu=cpu] [-misa=isa] [-mabi=abi] [-mall-ext] [-m[no-]16-bit] [-m[no-]perf-ext] [-m[no-]perf2-ext] [-m[no-]string-ext] [-m[no-]dsp-ext] [-m[no-]mac] [-m[no-]div] [-m[no-]audio-isa-ext] [-m[no-]fpu-sp-ext] [-m[no-]fpu-dp-ext] [-m[no-]fpu-fma] [-mfpu-freg=FREG] [-mreduced-regs] [-mfull-regs] [-m[no-]dx-regs] [-mpic] [-mno-relax] [-mb2bb] Target PDP11 options: [-mpic|-mno-pic] [-mall] [-mno-extensions] [-mextension|-mno-extension] [-mcpu] [-mmachine] Target picoJava options: [-mb|-me] Target PowerPC options: [-a32|-a64] [-mpwrx|-mpwr2|-mpwr|-m601|-mppc|-mppc32|-m603|-m604|-m403|-m405| -m440|-m464|-m476|-m7400|-m7410|-m7450|-m7455|-m750cl|-mgekko| -mbroadway|-mppc64|-m620|-me500|-e500x2|-me500mc|-me500mc64|-me5500| -me6500|-mppc64bridge|-mbooke|-mpower4|-mpwr4|-mpower5|-mpwr5|-mpwr5x| -mpower6|-mpwr6|-mpower7|-mpwr7|-mpower8|-mpwr8|-mpower9|-mpwr9-ma2| -mcell|-mspe|-mspe2|-mtitan|-me300|-mcom] [-many] [-maltivec|-mvsx|-mhtm|-mvle] [-mregnames|-mno-regnames] [-mrelocatable|-mrelocatable-lib|-K PIC] [-memb] [-mlittle|-mlittle-endian|-le|-mbig|-mbig-endian|-be] [-msolaris|-mno-solaris] [-nops=count] Target PRU options: [-link-relax] [-mnolink-relax] [-mno-warn-regname-label] Target RISC-V options: [-fpic|-fPIC|-fno-pic] [-march=ISA] [-mabi=ABI] [-mlittle-endian|-mbig-endian] Target RL78 options: [-mg10] [-m32bit-doubles|-m64bit-doubles] Target RX options: [-mlittle-endian|-mbig-endian] [-m32bit-doubles|-m64bit-doubles] [-muse-conventional-section-names] [-msmall-data-limit] [-mpid] [-mrelax] [-mint-register=number] [-mgcc-abi|-mrx-abi] Target s390 options: [-m31|-m64] [-mesa|-mzarch] [-march=CPU] [-mregnames|-mno-regnames] [-mwarn-areg-zero] Target SCORE options: [-EB][-EL][-FIXDD][-NWARN] [-SCORE5][-SCORE5U][-SCORE7][-SCORE3] [-march=score7][-march=score3] [-USE_R1][-KPIC][-O0][-G num][-V] Target SPARC options: [-Av6|-Av7|-Av8|-Aleon|-Asparclet|-Asparclite -Av8plus|-Av8plusa|-Av8plusb|-Av8plusc|-Av8plusd -Av8plusv|-Av8plusm|-Av9|-Av9a|-Av9b|-Av9c -Av9d|-Av9e|-Av9v|-Av9m|-Asparc|-Asparcvis -Asparcvis2|-Asparcfmaf|-Asparcima|-Asparcvis3 -Asparcvisr|-Asparc5] [-xarch=v8plus|-xarch=v8plusa]|-xarch=v8plusb|-xarch=v8plusc -xarch=v8plusd|-xarch=v8plusv|-xarch=v8plusm|-xarch=v9 -xarch=v9a|-xarch=v9b|-xarch=v9c|-xarch=v9d|-xarch=v9e -xarch=v9v|-xarch=v9m|-xarch=sparc|-xarch=sparcvis -xarch=sparcvis2|-xarch=sparcfmaf|-xarch=sparcima -xarch=sparcvis3|-xarch=sparcvisr|-xarch=sparc5 -bump] [-32|-64] [--enforce-aligned-data][--dcti-couples-detect] Target TIC54X options: [-mcpu=54[123589]|-mcpu=54[56]lp] [-mfar-mode|-mf] [-merrors-to-file <filename>|-me <filename>] Target TIC6X options: [-march=arch] [-mbig-endian|-mlittle-endian] [-mdsbt|-mno-dsbt] [-mpid=no|-mpid=near|-mpid=far] [-mpic|-mno-pic] Target TILE-Gx options: [-m32|-m64][-EB][-EL] Target Visium options: [-mtune=arch] Target Xtensa options: [--[no-]text-section-literals] [--[no-]auto-litpools] [--[no-]absolute-literals] [--[no-]target-align] [--[no-]longcalls] [--[no-]transform] [--rename-section oldname=newname] [--[no-]trampolines] [--abi-windowed|--abi-call0] Target Z80 options: [-march=CPU[-EXT][+EXT]] [-local-prefix=PREFIX] [-colonless] [-sdcc] [-fp-s=FORMAT] [-fp-d=FORMAT] DESCRIPTION top GNU as is really a family of assemblers. If you use (or have used) the GNU assembler on one architecture, you should find a fairly similar environment when you use it on another architecture. Each version has much in common with the others, including object file formats, most assembler directives (often called pseudo-ops) and assembler syntax. as is primarily intended to assemble the output of the GNU C compiler "gcc" for use by the linker "ld". Nevertheless, we've tried to make as assemble correctly everything that other assemblers for the same machine would assemble. Any exceptions are documented explicitly. This doesn't mean as always uses the same syntax as another assembler for the same architecture; for example, we know of several incompatible versions of 680x0 assembly language syntax. Each time you run as it assembles exactly one source program. The source program is made up of one or more files. (The standard input is also a file.) You give as a command line that has zero or more input file names. The input files are read (from left file name to right). A command-line argument (in any position) that has no special meaning is taken to be an input file name. If you give as no file names it attempts to read one input file from the as standard input, which is normally your terminal. You may have to type ctl-D to tell as there is no more program to assemble. Use -- if you need to explicitly name the standard input file in your command line. If the source is empty, as produces a small, empty object file. as may write warnings and error messages to the standard error file (usually your terminal). This should not happen when a compiler runs as automatically. Warnings report an assumption made so that as could keep assembling a flawed program; errors report a grave problem that stops the assembly. If you are invoking as via the GNU C compiler, you can use the -Wa option to pass arguments through to the assembler. The assembler arguments must be separated from each other (and the -Wa) by commas. For example: gcc -c -g -O -Wa,-alh,-L file.c This passes two options to the assembler: -alh (emit a listing to standard output with high-level and assembly source) and -L (retain local symbols in the symbol table). Usually you do not need to use this -Wa mechanism, since many compiler command-line options are automatically passed to the assembler by the compiler. (You can call the GNU compiler driver with the -v option to see precisely what options it passes to each compilation pass, including the assembler.) OPTIONS top @file Read command-line options from file. The options read are inserted in place of the original @file option. If file does not exist, or cannot be read, then the option will be treated literally, and not removed. Options in file are separated by whitespace. A whitespace character may be included in an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) may be included by prefixing the character to be included with a backslash. The file may itself contain additional @file options; any such options will be processed recursively. -a[cdghlmns] Turn on listings, in any of a variety of ways: -ac omit false conditionals -ad omit debugging directives -ag include general information, like as version and options passed -ah include high-level source -al include assembly -am include macro expansions -an omit forms processing -as include symbols =file set the name of the listing file You may combine these options; for example, use -aln for assembly listing without forms processing. The =file option, if used, must be the last one. By itself, -a defaults to -ahls. --alternate Begin in alternate macro mode. --compress-debug-sections Compress DWARF debug sections using zlib with SHF_COMPRESSED from the ELF ABI. The resulting object file may not be compatible with older linkers and object file utilities. Note if compression would make a given section larger then it is not compressed. --compress-debug-sections=none --compress-debug-sections=zlib --compress-debug-sections=zlib-gnu --compress-debug-sections=zlib-gabi --compress-debug-sections=zstd These options control how DWARF debug sections are compressed. --compress-debug-sections=none is equivalent to --nocompress-debug-sections. --compress-debug-sections=zlib and --compress-debug-sections=zlib-gabi are equivalent to --compress-debug-sections. --compress-debug-sections=zlib-gnu compresses DWARF debug sections using the obsoleted zlib-gnu format. The debug sections are renamed to begin with .zdebug. --compress-debug-sections=zstd compresses DWARF debug sections using zstd. Note - if compression would actually make a section larger, then it is not compressed nor renamed. --nocompress-debug-sections Do not compress DWARF debug sections. This is usually the default for all targets except the x86/x86_64, but a configure time option can be used to override this. -D Enable denugging in target specific backends, if supported. Otherwise ignored. Even if ignored, this option is accepted for script compatibility with calls to other assemblers. --debug-prefix-map old=new When assembling files in directory old, record debugging information describing them as in new instead. --defsym sym=value Define the symbol sym to be value before assembling the input file. value must be an integer constant. As in C, a leading 0x indicates a hexadecimal value, and a leading 0 indicates an octal value. The value of the symbol can be overridden inside a source file via the use of a ".set" pseudo-op. --dump-config Displays how the assembler is configured and then exits. --elf-stt-common=no --elf-stt-common=yes These options control whether the ELF assembler should generate common symbols with the "STT_COMMON" type. The default can be controlled by a configure option --enable-elf-stt-common. --emulation=name If the assembler is configured to support multiple different target configurations then this option can be used to select the desired form. -f "fast"---skip whitespace and comment preprocessing (assume source is compiler output). -g --gen-debug Generate debugging information for each assembler source line using whichever debug format is preferred by the target. This currently means either STABS, ECOFF or DWARF2. When the debug format is DWARF then a ".debug_info" and ".debug_line" section is only emitted when the assembly file doesn't generate one itself. --gstabs Generate stabs debugging information for each assembler line. This may help debugging assembler code, if the debugger can handle it. --gstabs+ Generate stabs debugging information for each assembler line, with GNU extensions that probably only gdb can handle, and that could make other debuggers crash or refuse to read your program. This may help debugging assembler code. Currently the only GNU extension is the location of the current working directory at assembling time. --gdwarf-2 Generate DWARF2 debugging information for each assembler line. This may help debugging assembler code, if the debugger can handle it. Note---this option is only supported by some targets, not all of them. --gdwarf-3 This option is the same as the --gdwarf-2 option, except that it allows for the possibility of the generation of extra debug information as per version 3 of the DWARF specification. Note - enabling this option does not guarantee the generation of any extra information, the choice to do so is on a per target basis. --gdwarf-4 This option is the same as the --gdwarf-2 option, except that it allows for the possibility of the generation of extra debug information as per version 4 of the DWARF specification. Note - enabling this option does not guarantee the generation of any extra information, the choice to do so is on a per target basis. --gdwarf-5 This option is the same as the --gdwarf-2 option, except that it allows for the possibility of the generation of extra debug information as per version 5 of the DWARF specification. Note - enabling this option does not guarantee the generation of any extra information, the choice to do so is on a per target basis. --gdwarf-sections Instead of creating a .debug_line section, create a series of .debug_line.foo sections where foo is the name of the corresponding code section. For example a code section called .text.func will have its dwarf line number information placed into a section called .debug_line.text.func. If the code section is just called .text then debug line section will still be called just .debug_line without any suffix. --gdwarf-cie-version=version Control which version of DWARF Common Information Entries (CIEs) are produced. When this flag is not specificed the default is version 1, though some targets can modify this default. Other possible values for version are 3 or 4. --generate-missing-build-notes=yes --generate-missing-build-notes=no These options control whether the ELF assembler should generate GNU Build attribute notes if none are present in the input sources. The default can be controlled by the --enable-generate-build-notes configure option. --gsframe --gsframe Create .sframe section from CFI directives. --hash-size N Ignored. Supported for command line compatibility with other assemblers. --help Print a summary of the command-line options and exit. --target-help Print a summary of all target specific options and exit. -I dir Add directory dir to the search list for ".include" directives. -J Don't warn about signed overflow. -K Issue warnings when difference tables altered for long displacements. -L --keep-locals Keep (in the symbol table) local symbols. These symbols start with system-specific local label prefixes, typically .L for ELF systems or L for traditional a.out systems. --listing-lhs-width=number Set the maximum width, in words, of the output data column for an assembler listing to number. --listing-lhs-width2=number Set the maximum width, in words, of the output data column for continuation lines in an assembler listing to number. --listing-rhs-width=number Set the maximum width of an input source line, as displayed in a listing, to number bytes. --listing-cont-lines=number Set the maximum number of lines printed in a listing for a single line of input to number + 1. --multibyte-handling=allow --multibyte-handling=warn --multibyte-handling=warn-sym-only --multibyte-handling=warn_sym_only Controls how the assembler handles multibyte characters in the input. The default (which can be restored by using the allow argument) is to allow such characters without complaint. Using the warn argument will make the assembler generate a warning message whenever any multibyte character is encountered. Using the warn-sym-only argument will only cause a warning to be generated when a symbol is defined with a name that contains multibyte characters. (References to undefined symbols will not generate a warning). --no-pad-sections Stop the assembler for padding the ends of output sections to the alignment of that section. The default is to pad the sections, but this can waste space which might be needed on targets which have tight memory constraints. -o objfile Name the object-file output from as objfile. -R Fold the data section into the text section. --reduce-memory-overheads Ignored. Supported for compatibility with tools that apss the same option to both the assembler and the linker. --sectname-subst Honor substitution sequences in section names. --size-check=error --size-check=warning Issue an error or warning for invalid ELF .size directive. --statistics Print the maximum space (in bytes) and total time (in seconds) used by assembly. --strip-local-absolute Remove local absolute symbols from the outgoing symbol table. -v -version Print the as version. --version Print the as version and exit. -W --no-warn Suppress warning messages. --fatal-warnings Treat warnings as errors. --warn Don't suppress warning messages or treat them as errors. -w Ignored. -x Ignored. -Z Generate an object file even after errors. -- | files ... Standard input, or source files to assemble. The following options are available when as is configured for the 64-bit mode of the ARM Architecture (AArch64). -EB This option specifies that the output generated by the assembler should be marked as being encoded for a big-endian processor. -EL This option specifies that the output generated by the assembler should be marked as being encoded for a little- endian processor. -mabi=abi Specify which ABI the source code uses. The recognized arguments are: "ilp32" and "lp64", which decides the generated object file in ELF32 and ELF64 format respectively. The default is "lp64". -mcpu=processor[+extension...] This option specifies the target processor. The assembler will issue an error message if an attempt is made to assemble an instruction which will not execute on the target processor. The following processor names are recognized: "cortex-a34", "cortex-a35", "cortex-a53", "cortex-a55", "cortex-a57", "cortex-a65", "cortex-a65ae", "cortex-a72", "cortex-a73", "cortex-a75", "cortex-a76", "cortex-a76ae", "cortex-a77", "cortex-a78", "cortex-a78ae", "cortex-a78c", "cortex-a510", "cortex-a710", "ares", "exynos-m1", "falkor", "neoverse-n1", "neoverse-n2", "neoverse-e1", "neoverse-v1", "qdf24xx", "saphira", "thunderx", "vulcan", "xgene1" "xgene2", "cortex-r82", "cortex-x1", and "cortex-x2". The special name "all" may be used to allow the assembler to accept instructions valid for any supported processor, including all optional extensions. In addition to the basic instruction set, the assembler can be told to accept, or restrict, various extension mnemonics that extend the processor. If some implementations of a particular processor can have an extension, then then those extensions are automatically enabled. Consequently, you will not normally have to specify any additional extensions. -march=architecture[+extension...] This option specifies the target architecture. The assembler will issue an error message if an attempt is made to assemble an instruction which will not execute on the target architecture. The following architecture names are recognized: "armv8-a", "armv8.1-a", "armv8.2-a", "armv8.3-a", "armv8.4-a" "armv8.5-a", "armv8.6-a", "armv8.7-a", "armv8.8-a", "armv8-r", "armv9-a", "armv9.1-a", "armv9.2-a", and "armv9.3-a". If both -mcpu and -march are specified, the assembler will use the setting for -mcpu. If neither are specified, the assembler will default to -mcpu=all. The architecture option can be extended with the same instruction set extension options as the -mcpu option. Unlike -mcpu, extensions are not always enabled by default, -mverbose-error This option enables verbose error messages for AArch64 gas. This option is enabled by default. -mno-verbose-error This option disables verbose error messages in AArch64 gas. The following options are available when as is configured for an Alpha processor. -mcpu This option specifies the target processor. If an attempt is made to assemble an instruction which will not execute on the target processor, the assembler may either expand the instruction as a macro or issue an error message. This option is equivalent to the ".arch" directive. The following processor names are recognized: 21064, "21064a", 21066, 21068, 21164, "21164a", "21164pc", 21264, "21264a", "21264b", "ev4", "ev5", "lca45", "ev5", "ev56", "pca56", "ev6", "ev67", "ev68". The special name "all" may be used to allow the assembler to accept instructions valid for any Alpha processor. In order to support existing practice in OSF/1 with respect to ".arch", and existing practice within MILO (the Linux ARC bootloader), the numbered processor names (e.g. 21064) enable the processor-specific PALcode instructions, while the "electro-vlasic" names (e.g. "ev4") do not. -mdebug -no-mdebug Enables or disables the generation of ".mdebug" encapsulation for stabs directives and procedure descriptors. The default is to automatically enable ".mdebug" when the first stabs directive is seen. -relax This option forces all relocations to be put into the object file, instead of saving space and resolving some relocations at assembly time. Note that this option does not propagate all symbol arithmetic into the object file, because not all symbol arithmetic can be represented. However, the option can still be useful in specific applications. -replace -noreplace Enables or disables the optimization of procedure calls, both at assemblage and at link time. These options are only available for VMS targets and "-replace" is the default. See section 1.4.1 of the OpenVMS Linker Utility Manual. -g This option is used when the compiler generates debug information. When gcc is using mips-tfile to generate debug information for ECOFF, local labels must be passed through to the object file. Otherwise this option has no effect. -Gsize A local common symbol larger than size is placed in ".bss", while smaller symbols are placed in ".sbss". -F -32addr These options are ignored for backward compatibility. The following options are available when as is configured for an ARC processor. -mcpu=cpu This option selects the core processor variant. -EB | -EL Select either big-endian (-EB) or little-endian (-EL) output. -mcode-density Enable Code Density extension instructions. The following options are available when as is configured for the ARM processor family. -mcpu=processor[+extension...] Specify which ARM processor variant is the target. -march=architecture[+extension...] Specify which ARM architecture variant is used by the target. -mfpu=floating-point-format Select which Floating Point architecture is the target. -mfloat-abi=abi Select which floating point ABI is in use. -mthumb Enable Thumb only instruction decoding. -mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant Select which procedure calling convention is in use. -EB | -EL Select either big-endian (-EB) or little-endian (-EL) output. -mthumb-interwork Specify that the code has been generated with interworking between Thumb and ARM code in mind. -mccs Turns on CodeComposer Studio assembly syntax compatibility mode. -k Specify that PIC code has been generated. The following options are available when as is configured for the Blackfin processor family. -mcpu=processor[-sirevision] This option specifies the target processor. The optional sirevision is not used in assembler. It's here such that GCC can easily pass down its "-mcpu=" option. The assembler will issue an error message if an attempt is made to assemble an instruction which will not execute on the target processor. The following processor names are recognized: "bf504", "bf506", "bf512", "bf514", "bf516", "bf518", "bf522", "bf523", "bf524", "bf525", "bf526", "bf527", "bf531", "bf532", "bf533", "bf534", "bf535" (not implemented yet), "bf536", "bf537", "bf538", "bf539", "bf542", "bf542m", "bf544", "bf544m", "bf547", "bf547m", "bf548", "bf548m", "bf549", "bf549m", "bf561", and "bf592". -mfdpic Assemble for the FDPIC ABI. -mno-fdpic -mnopic Disable -mfdpic. The following options are available when as is configured for the Linux kernel BPF processor family. @chapter BPF Dependent Features Options -EB This option specifies that the assembler should emit big- endian eBPF. -EL This option specifies that the assembler should emit little- endian eBPF. Note that if no endianness option is specified in the command line, the host endianness is used. See the info pages for documentation of the CRIS-specific options. The following options are available when as is configured for the C-SKY processor family. -march=archname Assemble for architecture archname. The --help option lists valid values for archname. -mcpu=cpuname Assemble for architecture cpuname. The --help option lists valid values for cpuname. -EL -mlittle-endian Generate little-endian output. -EB -mbig-endian Generate big-endian output. -fpic -pic Generate position-independent code. -mljump -mno-ljump Enable/disable transformation of the short branch instructions "jbf", "jbt", and "jbr" to "jmpi". This option is for V2 processors only. It is ignored on CK801 and CK802 targets, which do not support the "jmpi" instruction, and is enabled by default for other processors. -mbranch-stub -mno-branch-stub Pass through "R_CKCORE_PCREL_IMM26BY2" relocations for "bsr" instructions to the linker. This option is only available for bare-metal C-SKY V2 ELF targets, where it is enabled by default. It cannot be used in code that will be dynamically linked against shared libraries. -force2bsr -mforce2bsr -no-force2bsr -mno-force2bsr Enable/disable transformation of "jbsr" instructions to "bsr". This option is always enabled (and -mno-force2bsr is ignored) for CK801/CK802 targets. It is also always enabled when -mbranch-stub is in effect. -jsri2bsr -mjsri2bsr -no-jsri2bsr -mno-jsri2bsr Enable/disable transformation of "jsri" instructions to "bsr". This option is enabled by default. -mnolrw -mno-lrw Enable/disable transformation of "lrw" instructions into a "movih"/"ori" pair. -melrw -mno-elrw Enable/disable extended "lrw" instructions. This option is enabled by default for CK800-series processors. -mlaf -mliterals-after-func -mno-laf -mno-literals-after-func Enable/disable placement of literal pools after each function. -mlabr -mliterals-after-br -mno-labr -mnoliterals-after-br Enable/disable placement of literal pools after unconditional branches. This option is enabled by default. -mistack -mno-istack Enable/disable interrupt stack instructions. This option is enabled by default on CK801, CK802, and CK802 processors. The following options explicitly enable certain optional instructions. These features are also enabled implicitly by using "-mcpu=" to specify a processor that supports it. -mhard-float Enable hard float instructions. -mmp Enable multiprocessor instructions. -mcp Enable coprocessor instructions. -mcache Enable cache prefetch instruction. -msecurity Enable C-SKY security instructions. -mtrust Enable C-SKY trust instructions. -mdsp Enable DSP instructions. -medsp Enable enhanced DSP instructions. -mvdsp Enable vector DSP instructions. The following options are available when as is configured for an Epiphany processor. -mepiphany Specifies that the both 32 and 16 bit instructions are allowed. This is the default behavior. -mepiphany16 Restricts the permitted instructions to just the 16 bit set. The following options are available when as is configured for an H8/300 processor. @chapter H8/300 Dependent Features Options The Renesas H8/300 version of "as" has one machine-dependent option: -h-tick-hex Support H'00 style hex constants in addition to 0x00 style. -mach=name Sets the H8300 machine variant. The following machine names are recognised: "h8300h", "h8300hn", "h8300s", "h8300sn", "h8300sx" and "h8300sxn". The following options are available when as is configured for an i386 processor. --32 | --x32 | --64 Select the word size, either 32 bits or 64 bits. --32 implies Intel i386 architecture, while --x32 and --64 imply AMD x86-64 architecture with 32-bit or 64-bit word-size respectively. These options are only available with the ELF object file format, and require that the necessary BFD support has been included (on a 32-bit platform you have to add --enable-64-bit-bfd to configure enable 64-bit usage and use x86-64 as target platform). -n By default, x86 GAS replaces multiple nop instructions used for alignment within code sections with multi-byte nop instructions such as leal 0(%esi,1),%esi. This switch disables the optimization if a single byte nop (0x90) is explicitly specified as the fill byte for alignment. --divide On SVR4-derived platforms, the character / is treated as a comment character, which means that it cannot be used in expressions. The --divide option turns / into a normal character. This does not disable / at the beginning of a line starting a comment, or affect using # for starting a comment. -march=CPU[+EXTENSION...] This option specifies the target processor. The assembler will issue an error message if an attempt is made to assemble an instruction which will not execute on the target processor. The following processor names are recognized: "i8086", "i186", "i286", "i386", "i486", "i586", "i686", "pentium", "pentiumpro", "pentiumii", "pentiumiii", "pentium4", "prescott", "nocona", "core", "core2", "corei7", "iamcu", "k6", "k6_2", "athlon", "opteron", "k8", "amdfam10", "bdver1", "bdver2", "bdver3", "bdver4", "znver1", "znver2", "znver3", "znver4", "btver1", "btver2", "generic32" and "generic64". In addition to the basic instruction set, the assembler can be told to accept various extension mnemonics. For example, "-march=i686+sse4+vmx" extends i686 with sse4 and vmx. The following extensions are currently supported: 8087, 287, 387, 687, "cmov", "fxsr", "mmx", "sse", "sse2", "sse3", "sse4a", "ssse3", "sse4.1", "sse4.2", "sse4", "avx", "avx2", "lahf_sahf", "monitor", "adx", "rdseed", "prfchw", "smap", "mpx", "sha", "rdpid", "ptwrite", "cet", "gfni", "vaes", "vpclmulqdq", "prefetchwt1", "clflushopt", "se1", "clwb", "movdiri", "movdir64b", "enqcmd", "serialize", "tsxldtrk", "kl", "widekl", "hreset", "avx512f", "avx512cd", "avx512er", "avx512pf", "avx512vl", "avx512bw", "avx512dq", "avx512ifma", "avx512vbmi", "avx512_4fmaps", "avx512_4vnniw", "avx512_vpopcntdq", "avx512_vbmi2", "avx512_vnni", "avx512_bitalg", "avx512_vp2intersect", "tdx", "avx512_bf16", "avx_vnni", "avx512_fp16", "prefetchi", "avx_ifma", "avx_vnni_int8", "cmpccxadd", "wrmsrns", "msrlist", "avx_ne_convert", "rao_int", "fred", "lkgs", "amx_int8", "amx_bf16", "amx_fp16", "amx_complex", "amx_tile", "vmx", "vmfunc", "smx", "xsave", "xsaveopt", "xsavec", "xsaves", "aes", "pclmul", "fsgsbase", "rdrnd", "f16c", "bmi2", "fma", "movbe", "ept", "lzcnt", "popcnt", "hle", "rtm", "tsx", "invpcid", "clflush", "mwaitx", "clzero", "wbnoinvd", "pconfig", "waitpkg", "uintr", "cldemote", "rdpru", "mcommit", "sev_es", "lwp", "fma4", "xop", "cx16", "syscall", "rdtscp", "3dnow", "3dnowa", "sse4a", "sse5", "snp", "invlpgb", "tlbsync", "svme" and "padlock". Note that these extension mnemonics can be prefixed with "no" to revoke the respective (and any dependent) functionality. When the ".arch" directive is used with -march, the ".arch" directive will take precedent. -mtune=CPU This option specifies a processor to optimize for. When used in conjunction with the -march option, only instructions of the processor specified by the -march option will be generated. Valid CPU values are identical to the processor list of -march=CPU. -msse2avx This option specifies that the assembler should encode SSE instructions with VEX prefix. -muse-unaligned-vector-move This option specifies that the assembler should encode aligned vector move as unaligned vector move. -msse-check=none -msse-check=warning -msse-check=error These options control if the assembler should check SSE instructions. -msse-check=none will make the assembler not to check SSE instructions, which is the default. -msse-check=warning will make the assembler issue a warning for any SSE instruction. -msse-check=error will make the assembler issue an error for any SSE instruction. -mavxscalar=128 -mavxscalar=256 These options control how the assembler should encode scalar AVX instructions. -mavxscalar=128 will encode scalar AVX instructions with 128bit vector length, which is the default. -mavxscalar=256 will encode scalar AVX instructions with 256bit vector length. WARNING: Don't use this for production code - due to CPU errata the resulting code may not work on certain models. -mvexwig=0 -mvexwig=1 These options control how the assembler should encode VEX.W-ignored (WIG) VEX instructions. -mvexwig=0 will encode WIG VEX instructions with vex.w = 0, which is the default. -mvexwig=1 will encode WIG EVEX instructions with vex.w = 1. WARNING: Don't use this for production code - due to CPU errata the resulting code may not work on certain models. -mevexlig=128 -mevexlig=256 -mevexlig=512 These options control how the assembler should encode length- ignored (LIG) EVEX instructions. -mevexlig=128 will encode LIG EVEX instructions with 128bit vector length, which is the default. -mevexlig=256 and -mevexlig=512 will encode LIG EVEX instructions with 256bit and 512bit vector length, respectively. -mevexwig=0 -mevexwig=1 These options control how the assembler should encode w-ignored (WIG) EVEX instructions. -mevexwig=0 will encode WIG EVEX instructions with evex.w = 0, which is the default. -mevexwig=1 will encode WIG EVEX instructions with evex.w = 1. -mmnemonic=att -mmnemonic=intel This option specifies instruction mnemonic for matching instructions. The ".att_mnemonic" and ".intel_mnemonic" directives will take precedent. -msyntax=att -msyntax=intel This option specifies instruction syntax when processing instructions. The ".att_syntax" and ".intel_syntax" directives will take precedent. -mnaked-reg This option specifies that registers don't require a % prefix. The ".att_syntax" and ".intel_syntax" directives will take precedent. -madd-bnd-prefix This option forces the assembler to add BND prefix to all branches, even if such prefix was not explicitly specified in the source code. -mno-shared On ELF target, the assembler normally optimizes out non-PLT relocations against defined non-weak global branch targets with default visibility. The -mshared option tells the assembler to generate code which may go into a shared library where all non-weak global branch targets with default visibility can be preempted. The resulting code is slightly bigger. This option only affects the handling of branch instructions. -mbig-obj On PE/COFF target this option forces the use of big object file format, which allows more than 32768 sections. -momit-lock-prefix=no -momit-lock-prefix=yes These options control how the assembler should encode lock prefix. This option is intended as a workaround for processors, that fail on lock prefix. This option can only be safely used with single-core, single-thread computers -momit-lock-prefix=yes will omit all lock prefixes. -momit-lock-prefix=no will encode lock prefix as usual, which is the default. -mfence-as-lock-add=no -mfence-as-lock-add=yes These options control how the assembler should encode lfence, mfence and sfence. -mfence-as-lock-add=yes will encode lfence, mfence and sfence as lock addl $0x0, (%rsp) in 64-bit mode and lock addl $0x0, (%esp) in 32-bit mode. -mfence-as-lock-add=no will encode lfence, mfence and sfence as usual, which is the default. -mrelax-relocations=no -mrelax-relocations=yes These options control whether the assembler should generate relax relocations, R_386_GOT32X, in 32-bit mode, or R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX, in 64-bit mode. -mrelax-relocations=yes will generate relax relocations. -mrelax-relocations=no will not generate relax relocations. The default can be controlled by a configure option --enable-x86-relax-relocations. -malign-branch-boundary=NUM This option controls how the assembler should align branches with segment prefixes or NOP. NUM must be a power of 2. It should be 0 or no less than 16. Branches will be aligned within NUM byte boundary. -malign-branch-boundary=0, which is the default, doesn't align branches. -malign-branch=TYPE[+TYPE...] This option specifies types of branches to align. TYPE is combination of jcc, which aligns conditional jumps, fused, which aligns fused conditional jumps, jmp, which aligns unconditional jumps, call which aligns calls, ret, which aligns rets, indirect, which aligns indirect jumps and calls. The default is -malign-branch=jcc+fused+jmp. -malign-branch-prefix-size=NUM This option specifies the maximum number of prefixes on an instruction to align branches. NUM should be between 0 and 5. The default NUM is 5. -mbranches-within-32B-boundaries This option aligns conditional jumps, fused conditional jumps and unconditional jumps within 32 byte boundary with up to 5 segment prefixes on an instruction. It is equivalent to -malign-branch-boundary=32 -malign-branch=jcc+fused+jmp -malign-branch-prefix-size=5. The default doesn't align branches. -mlfence-after-load=no -mlfence-after-load=yes These options control whether the assembler should generate lfence after load instructions. -mlfence-after-load=yes will generate lfence. -mlfence-after-load=no will not generate lfence, which is the default. -mlfence-before-indirect-branch=none -mlfence-before-indirect-branch=all -mlfence-before-indirect-branch=register -mlfence-before-indirect-branch=memory These options control whether the assembler should generate lfence before indirect near branch instructions. -mlfence-before-indirect-branch=all will generate lfence before indirect near branch via register and issue a warning before indirect near branch via memory. It also implicitly sets -mlfence-before-ret=shl when there's no explicit -mlfence-before-ret=. -mlfence-before-indirect-branch=register will generate lfence before indirect near branch via register. -mlfence-before-indirect-branch=memory will issue a warning before indirect near branch via memory. -mlfence-before-indirect-branch=none will not generate lfence nor issue warning, which is the default. Note that lfence won't be generated before indirect near branch via register with -mlfence-after-load=yes since lfence will be generated after loading branch target register. -mlfence-before-ret=none -mlfence-before-ret=shl -mlfence-before-ret=or -mlfence-before-ret=yes -mlfence-before-ret=not These options control whether the assembler should generate lfence before ret. -mlfence-before-ret=or will generate generate or instruction with lfence. -mlfence-before-ret=shl/yes will generate shl instruction with lfence. -mlfence-before-ret=not will generate not instruction with lfence. -mlfence-before-ret=none will not generate lfence, which is the default. -mx86-used-note=no -mx86-used-note=yes These options control whether the assembler should generate GNU_PROPERTY_X86_ISA_1_USED and GNU_PROPERTY_X86_FEATURE_2_USED GNU property notes. The default can be controlled by the --enable-x86-used-note configure option. -mevexrcig=rne -mevexrcig=rd -mevexrcig=ru -mevexrcig=rz These options control how the assembler should encode SAE- only EVEX instructions. -mevexrcig=rne will encode RC bits of EVEX instruction with 00, which is the default. -mevexrcig=rd, -mevexrcig=ru and -mevexrcig=rz will encode SAE-only EVEX instructions with 01, 10 and 11 RC bits, respectively. -mamd64 -mintel64 This option specifies that the assembler should accept only AMD64 or Intel64 ISA in 64-bit mode. The default is to accept common, Intel64 only and AMD64 ISAs. -O0 | -O | -O1 | -O2 | -Os Optimize instruction encoding with smaller instruction size. -O and -O1 encode 64-bit register load instructions with 64-bit immediate as 32-bit register load instructions with 31-bit or 32-bits immediates, encode 64-bit register clearing instructions with 32-bit register clearing instructions, encode 256-bit/512-bit VEX/EVEX vector register clearing instructions with 128-bit VEX vector register clearing instructions, encode 128-bit/256-bit EVEX vector register load/store instructions with VEX vector register load/store instructions, and encode 128-bit/256-bit EVEX packed integer logical instructions with 128-bit/256-bit VEX packed integer logical. -O2 includes -O1 optimization plus encodes 256-bit/512-bit EVEX vector register clearing instructions with 128-bit EVEX vector register clearing instructions. In 64-bit mode VEX encoded instructions with commutative source operands will also have their source operands swapped if this allows using the 2-byte VEX prefix form instead of the 3-byte one. Certain forms of AND as well as OR with the same (register) operand specified twice will also be changed to TEST. -Os includes -O2 optimization plus encodes 16-bit, 32-bit and 64-bit register tests with immediate as 8-bit register test with immediate. -O0 turns off this optimization. The following options are available when as is configured for the Ubicom IP2K series. -mip2022ext Specifies that the extended IP2022 instructions are allowed. -mip2022 Restores the default behaviour, which restricts the permitted instructions to just the basic IP2022 ones. The following options are available when as is configured for the Renesas M32C and M16C processors. -m32c Assemble M32C instructions. -m16c Assemble M16C instructions (the default). -relax Enable support for link-time relaxations. -h-tick-hex Support H'00 style hex constants in addition to 0x00 style. The following options are available when as is configured for the Renesas M32R (formerly Mitsubishi M32R) series. --m32rx Specify which processor in the M32R family is the target. The default is normally the M32R, but this option changes it to the M32RX. --warn-explicit-parallel-conflicts or --Wp Produce warning messages when questionable parallel constructs are encountered. --no-warn-explicit-parallel-conflicts or --Wnp Do not produce warning messages when questionable parallel constructs are encountered. The following options are available when as is configured for the Motorola 68000 series. -l Shorten references to undefined symbols, to one word instead of two. -m68000 | -m68008 | -m68010 | -m68020 | -m68030 | -m68040 | -m68060 | -m68302 | -m68331 | -m68332 | -m68333 | -m68340 | -mcpu32 | -m5200 Specify what processor in the 68000 family is the target. The default is normally the 68020, but this can be changed at configuration time. -m68881 | -m68882 | -mno-68881 | -mno-68882 The target machine does (or does not) have a floating-point coprocessor. The default is to assume a coprocessor for 68020, 68030, and cpu32. Although the basic 68000 is not compatible with the 68881, a combination of the two can be specified, since it's possible to do emulation of the coprocessor instructions with the main processor. -m68851 | -mno-68851 The target machine does (or does not) have a memory- management unit coprocessor. The default is to assume an MMU for 68020 and up. The following options are available when as is configured for an Altera Nios II processor. -relax-section Replace identified out-of-range branches with PC-relative "jmp" sequences when possible. The generated code sequences are suitable for use in position-independent code, but there is a practical limit on the extended branch range because of the length of the sequences. This option is the default. -relax-all Replace branch instructions not determinable to be in range and all call instructions with "jmp" and "callr" sequences (respectively). This option generates absolute relocations against the target symbols and is not appropriate for position-independent code. -no-relax Do not replace any branches or calls. -EB Generate big-endian output. -EL Generate little-endian output. This is the default. -march=architecture This option specifies the target architecture. The assembler issues an error message if an attempt is made to assemble an instruction which will not execute on the target architecture. The following architecture names are recognized: "r1", "r2". The default is "r1". The following options are available when as is configured for a PRU processor. -mlink-relax Assume that LD would optimize LDI32 instructions by checking the upper 16 bits of the expression. If they are all zeros, then LD would shorten the LDI32 instruction to a single LDI. In such case "as" will output DIFF relocations for diff expressions. -mno-link-relax Assume that LD would not optimize LDI32 instructions. As a consequence, DIFF relocations will not be emitted. -mno-warn-regname-label Do not warn if a label name matches a register name. Usually assembler programmers will want this warning to be emitted. C compilers may want to turn this off. The following options are available when as is configured for a MIPS processor. -G num This option sets the largest size of an object that can be referenced implicitly with the "gp" register. It is only accepted for targets that use ECOFF format, such as a DECstation running Ultrix. The default value is 8. -EB Generate "big endian" format output. -EL Generate "little endian" format output. -mips1 -mips2 -mips3 -mips4 -mips5 -mips32 -mips32r2 -mips32r3 -mips32r5 -mips32r6 -mips64 -mips64r2 -mips64r3 -mips64r5 -mips64r6 Generate code for a particular MIPS Instruction Set Architecture level. -mips1 is an alias for -march=r3000, -mips2 is an alias for -march=r6000, -mips3 is an alias for -march=r4000 and -mips4 is an alias for -march=r8000. -mips5, -mips32, -mips32r2, -mips32r3, -mips32r5, -mips32r6, -mips64, -mips64r2, -mips64r3, -mips64r5, and -mips64r6 correspond to generic MIPS V, MIPS32, MIPS32 Release 2, MIPS32 Release 3, MIPS32 Release 5, MIPS32 Release 6, MIPS64, MIPS64 Release 2, MIPS64 Release 3, MIPS64 Release 5, and MIPS64 Release 6 ISA processors, respectively. -march=cpu Generate code for a particular MIPS CPU. -mtune=cpu Schedule and tune for a particular MIPS CPU. -mfix7000 -mno-fix7000 Cause nops to be inserted if the read of the destination register of an mfhi or mflo instruction occurs in the following two instructions. -mfix-rm7000 -mno-fix-rm7000 Cause nops to be inserted if a dmult or dmultu instruction is followed by a load instruction. -mfix-r5900 -mno-fix-r5900 Do not attempt to schedule the preceding instruction into the delay slot of a branch instruction placed at the end of a short loop of six instructions or fewer and always schedule a "nop" instruction there instead. The short loop bug under certain conditions causes loops to execute only once or twice, due to a hardware bug in the R5900 chip. -mdebug -no-mdebug Cause stabs-style debugging output to go into an ECOFF-style .mdebug section instead of the standard ELF .stabs sections. -mpdr -mno-pdr Control generation of ".pdr" sections. -mgp32 -mfp32 The register sizes are normally inferred from the ISA and ABI, but these flags force a certain group of registers to be treated as 32 bits wide at all times. -mgp32 controls the size of general-purpose registers and -mfp32 controls the size of floating-point registers. -mgp64 -mfp64 The register sizes are normally inferred from the ISA and ABI, but these flags force a certain group of registers to be treated as 64 bits wide at all times. -mgp64 controls the size of general-purpose registers and -mfp64 controls the size of floating-point registers. -mfpxx The register sizes are normally inferred from the ISA and ABI, but using this flag in combination with -mabi=32 enables an ABI variant which will operate correctly with floating- point registers which are 32 or 64 bits wide. -modd-spreg -mno-odd-spreg Enable use of floating-point operations on odd-numbered single-precision registers when supported by the ISA. -mfpxx implies -mno-odd-spreg, otherwise the default is -modd-spreg. -mips16 -no-mips16 Generate code for the MIPS 16 processor. This is equivalent to putting ".module mips16" at the start of the assembly file. -no-mips16 turns off this option. -mmips16e2 -mno-mips16e2 Enable the use of MIPS16e2 instructions in MIPS16 mode. This is equivalent to putting ".module mips16e2" at the start of the assembly file. -mno-mips16e2 turns off this option. -mmicromips -mno-micromips Generate code for the microMIPS processor. This is equivalent to putting ".module micromips" at the start of the assembly file. -mno-micromips turns off this option. This is equivalent to putting ".module nomicromips" at the start of the assembly file. -msmartmips -mno-smartmips Enables the SmartMIPS extension to the MIPS32 instruction set. This is equivalent to putting ".module smartmips" at the start of the assembly file. -mno-smartmips turns off this option. -mips3d -no-mips3d Generate code for the MIPS-3D Application Specific Extension. This tells the assembler to accept MIPS-3D instructions. -no-mips3d turns off this option. -mdmx -no-mdmx Generate code for the MDMX Application Specific Extension. This tells the assembler to accept MDMX instructions. -no-mdmx turns off this option. -mdsp -mno-dsp Generate code for the DSP Release 1 Application Specific Extension. This tells the assembler to accept DSP Release 1 instructions. -mno-dsp turns off this option. -mdspr2 -mno-dspr2 Generate code for the DSP Release 2 Application Specific Extension. This option implies -mdsp. This tells the assembler to accept DSP Release 2 instructions. -mno-dspr2 turns off this option. -mdspr3 -mno-dspr3 Generate code for the DSP Release 3 Application Specific Extension. This option implies -mdsp and -mdspr2. This tells the assembler to accept DSP Release 3 instructions. -mno-dspr3 turns off this option. -mmsa -mno-msa Generate code for the MIPS SIMD Architecture Extension. This tells the assembler to accept MSA instructions. -mno-msa turns off this option. -mxpa -mno-xpa Generate code for the MIPS eXtended Physical Address (XPA) Extension. This tells the assembler to accept XPA instructions. -mno-xpa turns off this option. -mmt -mno-mt Generate code for the MT Application Specific Extension. This tells the assembler to accept MT instructions. -mno-mt turns off this option. -mmcu -mno-mcu Generate code for the MCU Application Specific Extension. This tells the assembler to accept MCU instructions. -mno-mcu turns off this option. -mcrc -mno-crc Generate code for the MIPS cyclic redundancy check (CRC) Application Specific Extension. This tells the assembler to accept CRC instructions. -mno-crc turns off this option. -mginv -mno-ginv Generate code for the Global INValidate (GINV) Application Specific Extension. This tells the assembler to accept GINV instructions. -mno-ginv turns off this option. -mloongson-mmi -mno-loongson-mmi Generate code for the Loongson MultiMedia extensions Instructions (MMI) Application Specific Extension. This tells the assembler to accept MMI instructions. -mno-loongson-mmi turns off this option. -mloongson-cam -mno-loongson-cam Generate code for the Loongson Content Address Memory (CAM) instructions. This tells the assembler to accept Loongson CAM instructions. -mno-loongson-cam turns off this option. -mloongson-ext -mno-loongson-ext Generate code for the Loongson EXTensions (EXT) instructions. This tells the assembler to accept Loongson EXT instructions. -mno-loongson-ext turns off this option. -mloongson-ext2 -mno-loongson-ext2 Generate code for the Loongson EXTensions R2 (EXT2) instructions. This option implies -mloongson-ext. This tells the assembler to accept Loongson EXT2 instructions. -mno-loongson-ext2 turns off this option. -minsn32 -mno-insn32 Only use 32-bit instruction encodings when generating code for the microMIPS processor. This option inhibits the use of any 16-bit instructions. This is equivalent to putting ".set insn32" at the start of the assembly file. -mno-insn32 turns off this option. This is equivalent to putting ".set noinsn32" at the start of the assembly file. By default -mno-insn32 is selected, allowing all instructions to be used. --construct-floats --no-construct-floats The --no-construct-floats option disables the construction of double width floating point constants by loading the two halves of the value into the two single width floating point registers that make up the double width register. By default --construct-floats is selected, allowing construction of these floating point constants. --relax-branch --no-relax-branch The --relax-branch option enables the relaxation of out-of- range branches. By default --no-relax-branch is selected, causing any out-of-range branches to produce an error. -mignore-branch-isa -mno-ignore-branch-isa Ignore branch checks for invalid transitions between ISA modes. The semantics of branches does not provide for an ISA mode switch, so in most cases the ISA mode a branch has been encoded for has to be the same as the ISA mode of the branch's target label. Therefore GAS has checks implemented that verify in branch assembly that the two ISA modes match. -mignore-branch-isa disables these checks. By default -mno-ignore-branch-isa is selected, causing any invalid branch requiring a transition between ISA modes to produce an error. -mnan=encoding Select between the IEEE 754-2008 (-mnan=2008) or the legacy (-mnan=legacy) NaN encoding format. The latter is the default. --emulation=name This option was formerly used to switch between ELF and ECOFF output on targets like IRIX 5 that supported both. MIPS ECOFF support was removed in GAS 2.24, so the option now serves little purpose. It is retained for backwards compatibility. The available configuration names are: mipself, mipslelf and mipsbelf. Choosing mipself now has no effect, since the output is always ELF. mipslelf and mipsbelf select little- and big-endian output respectively, but -EL and -EB are now the preferred options instead. -nocpp as ignores this option. It is accepted for compatibility with the native tools. --trap --no-trap --break --no-break Control how to deal with multiplication overflow and division by zero. --trap or --no-break (which are synonyms) take a trap exception (and only work for Instruction Set Architecture level 2 and higher); --break or --no-trap (also synonyms, and the default) take a break exception. -n When this option is used, as will issue a warning every time it generates a nop instruction from a macro. The following options are available when as is configured for a LoongArch processor. -fpic -fPIC Generate position-independent code -fno-pic Don't generate position-independent code (default) The following options are available when as is configured for a Meta processor. "-mcpu=metac11" Generate code for Meta 1.1. "-mcpu=metac12" Generate code for Meta 1.2. "-mcpu=metac21" Generate code for Meta 2.1. "-mfpu=metac21" Allow code to use FPU hardware of Meta 2.1. See the info pages for documentation of the MMIX-specific options. The following options are available when as is configured for a NDS32 processor. "-O1" Optimize for performance. "-Os" Optimize for space. "-EL" Produce little endian data output. "-EB" Produce little endian data output. "-mpic" Generate PIC. "-mno-fp-as-gp-relax" Suppress fp-as-gp relaxation for this file. "-mb2bb-relax" Back-to-back branch optimization. "-mno-all-relax" Suppress all relaxation for this file. "-march=<arch name>" Assemble for architecture <arch name> which could be v3, v3j, v3m, v3f, v3s, v2, v2j, v2f, v2s. "-mbaseline=<baseline>" Assemble for baseline <baseline> which could be v2, v3, v3m. "-mfpu-freg=FREG" Specify a FPU configuration. "0 8 SP / 4 DP registers" "1 16 SP / 8 DP registers" "2 32 SP / 16 DP registers" "3 32 SP / 32 DP registers" "-mabi=abi" Specify a abi version <abi> could be v1, v2, v2fp, v2fpp. "-m[no-]mac" Enable/Disable Multiply instructions support. "-m[no-]div" Enable/Disable Divide instructions support. "-m[no-]16bit-ext" Enable/Disable 16-bit extension "-m[no-]dx-regs" Enable/Disable d0/d1 registers "-m[no-]perf-ext" Enable/Disable Performance extension "-m[no-]perf2-ext" Enable/Disable Performance extension 2 "-m[no-]string-ext" Enable/Disable String extension "-m[no-]reduced-regs" Enable/Disable Reduced Register configuration (GPR16) option "-m[no-]audio-isa-ext" Enable/Disable AUDIO ISA extension "-m[no-]fpu-sp-ext" Enable/Disable FPU SP extension "-m[no-]fpu-dp-ext" Enable/Disable FPU DP extension "-m[no-]fpu-fma" Enable/Disable FPU fused-multiply-add instructions "-mall-ext" Turn on all extensions and instructions support The following options are available when as is configured for a PowerPC processor. -a32 Generate ELF32 or XCOFF32. -a64 Generate ELF64 or XCOFF64. -K PIC Set EF_PPC_RELOCATABLE_LIB in ELF flags. -mpwrx | -mpwr2 Generate code for POWER/2 (RIOS2). -mpwr Generate code for POWER (RIOS1) -m601 Generate code for PowerPC 601. -mppc, -mppc32, -m603, -m604 Generate code for PowerPC 603/604. -m403, -m405 Generate code for PowerPC 403/405. -m440 Generate code for PowerPC 440. BookE and some 405 instructions. -m464 Generate code for PowerPC 464. -m476 Generate code for PowerPC 476. -m7400, -m7410, -m7450, -m7455 Generate code for PowerPC 7400/7410/7450/7455. -m750cl, -mgekko, -mbroadway Generate code for PowerPC 750CL/Gekko/Broadway. -m821, -m850, -m860 Generate code for PowerPC 821/850/860. -mppc64, -m620 Generate code for PowerPC 620/625/630. -me200z2, -me200z4 Generate code for e200 variants, e200z2 with LSP, e200z4 with SPE. -me300 Generate code for PowerPC e300 family. -me500, -me500x2 Generate code for Motorola e500 core complex. -me500mc Generate code for Freescale e500mc core complex. -me500mc64 Generate code for Freescale e500mc64 core complex. -me5500 Generate code for Freescale e5500 core complex. -me6500 Generate code for Freescale e6500 core complex. -mlsp Enable LSP instructions. (Disables SPE and SPE2.) -mspe Generate code for Motorola SPE instructions. (Disables LSP.) -mspe2 Generate code for Freescale SPE2 instructions. (Disables LSP.) -mtitan Generate code for AppliedMicro Titan core complex. -mppc64bridge Generate code for PowerPC 64, including bridge insns. -mbooke Generate code for 32-bit BookE. -ma2 Generate code for A2 architecture. -maltivec Generate code for processors with AltiVec instructions. -mvle Generate code for Freescale PowerPC VLE instructions. -mvsx Generate code for processors with Vector-Scalar (VSX) instructions. -mhtm Generate code for processors with Hardware Transactional Memory instructions. -mpower4, -mpwr4 Generate code for Power4 architecture. -mpower5, -mpwr5, -mpwr5x Generate code for Power5 architecture. -mpower6, -mpwr6 Generate code for Power6 architecture. -mpower7, -mpwr7 Generate code for Power7 architecture. -mpower8, -mpwr8 Generate code for Power8 architecture. -mpower9, -mpwr9 Generate code for Power9 architecture. -mpower10, -mpwr10 Generate code for Power10 architecture. -mfuture Generate code for 'future' architecture. -mcell -mcell Generate code for Cell Broadband Engine architecture. -mcom Generate code Power/PowerPC common instructions. -many Generate code for any architecture (PWR/PWRX/PPC). -mregnames Allow symbolic names for registers. -mno-regnames Do not allow symbolic names for registers. -mrelocatable Support for GCC's -mrelocatable option. -mrelocatable-lib Support for GCC's -mrelocatable-lib option. -memb Set PPC_EMB bit in ELF flags. -mlittle, -mlittle-endian, -le Generate code for a little endian machine. -mbig, -mbig-endian, -be Generate code for a big endian machine. -msolaris Generate code for Solaris. -mno-solaris Do not generate code for Solaris. -nops=count If an alignment directive inserts more than count nops, put a branch at the beginning to skip execution of the nops. The following options are available when as is configured for a RISC-V processor. -fpic -fPIC Generate position-independent code -fno-pic Don't generate position-independent code (default) -march=ISA Select the base isa, as specified by ISA. For example -march=rv32ima. If this option and the architecture attributes aren't set, then assembler will check the default configure setting --with-arch=ISA. -misa-spec=ISAspec Select the default isa spec version. If the version of ISA isn't set by -march, then assembler helps to set the version according to the default chosen spec. If this option isn't set, then assembler will check the default configure setting --with-isa-spec=ISAspec. -mpriv-spec=PRIVspec Select the privileged spec version. We can decide whether the CSR is valid or not according to the chosen spec. If this option and the privilege attributes aren't set, then assembler will check the default configure setting --with-priv-spec=PRIVspec. -mabi=ABI Selects the ABI, which is either "ilp32" or "lp64", optionally followed by "f", "d", or "q" to indicate single- precision, double-precision, or quad-precision floating-point calling convention, or none to indicate the soft-float calling convention. Also, "ilp32" can optionally be followed by "e" to indicate the RVE ABI, which is always soft-float. -mrelax Take advantage of linker relaxations to reduce the number of instructions required to materialize symbol addresses. (default) -mno-relax Don't do linker relaxations. -march-attr Generate the default contents for the riscv elf attribute section if the .attribute directives are not set. This section is used to record the information that a linker or runtime loader needs to check compatibility. This information includes ISA string, stack alignment requirement, unaligned memory accesses, and the major, minor and revision version of privileged specification. -mno-arch-attr Don't generate the default riscv elf attribute section if the .attribute directives are not set. -mcsr-check Enable the CSR checking for the ISA-dependent CRS and the read-only CSR. The ISA-dependent CSR are only valid when the specific ISA is set. The read-only CSR can not be written by the CSR instructions. -mno-csr-check Don't do CSR checking. -mlittle-endian Generate code for a little endian machine. -mbig-endian Generate code for a big endian machine. See the info pages for documentation of the RX-specific options. The following options are available when as is configured for the s390 processor family. -m31 -m64 Select the word size, either 31/32 bits or 64 bits. -mesa -mzarch Select the architecture mode, either the Enterprise System Architecture (esa) or the z/Architecture mode (zarch). -march=processor Specify which s390 processor variant is the target, g5 (or arch3), g6, z900 (or arch5), z990 (or arch6), z9-109, z9-ec (or arch7), z10 (or arch8), z196 (or arch9), zEC12 (or arch10), z13 (or arch11), z14 (or arch12), z15 (or arch13), or z16 (or arch14). -mregnames -mno-regnames Allow or disallow symbolic names for registers. -mwarn-areg-zero Warn whenever the operand for a base or index register has been specified but evaluates to zero. The following options are available when as is configured for a TMS320C6000 processor. -march=arch Enable (only) instructions from architecture arch. By default, all instructions are permitted. The following values of arch are accepted: "c62x", "c64x", "c64x+", "c67x", "c67x+", "c674x". -mdsbt -mno-dsbt The -mdsbt option causes the assembler to generate the "Tag_ABI_DSBT" attribute with a value of 1, indicating that the code is using DSBT addressing. The -mno-dsbt option, the default, causes the tag to have a value of 0, indicating that the code does not use DSBT addressing. The linker will emit a warning if objects of different type (DSBT and non-DSBT) are linked together. -mpid=no -mpid=near -mpid=far The -mpid= option causes the assembler to generate the "Tag_ABI_PID" attribute with a value indicating the form of data addressing used by the code. -mpid=no, the default, indicates position-dependent data addressing, -mpid=near indicates position-independent addressing with GOT accesses using near DP addressing, and -mpid=far indicates position- independent addressing with GOT accesses using far DP addressing. The linker will emit a warning if objects built with different settings of this option are linked together. -mpic -mno-pic The -mpic option causes the assembler to generate the "Tag_ABI_PIC" attribute with a value of 1, indicating that the code is using position-independent code addressing, The "-mno-pic" option, the default, causes the tag to have a value of 0, indicating position-dependent code addressing. The linker will emit a warning if objects of different type (position-dependent and position-independent) are linked together. -mbig-endian -mlittle-endian Generate code for the specified endianness. The default is little-endian. The following options are available when as is configured for a TILE-Gx processor. -m32 | -m64 Select the word size, either 32 bits or 64 bits. -EB | -EL Select the endianness, either big-endian (-EB) or little- endian (-EL). The following option is available when as is configured for a Visium processor. -mtune=arch This option specifies the target architecture. If an attempt is made to assemble an instruction that will not execute on the target architecture, the assembler will issue an error message. The following names are recognized: "mcm24" "mcm" "gr5" "gr6" The following options are available when as is configured for an Xtensa processor. --text-section-literals | --no-text-section-literals Control the treatment of literal pools. The default is --no-text-section-literals, which places literals in separate sections in the output file. This allows the literal pool to be placed in a data RAM/ROM. With --text-section-literals, the literals are interspersed in the text section in order to keep them as close as possible to their references. This may be necessary for large assembly files, where the literals would otherwise be out of range of the "L32R" instructions in the text section. Literals are grouped into pools following ".literal_position" directives or preceding "ENTRY" instructions. These options only affect literals referenced via PC-relative "L32R" instructions; literals for absolute mode "L32R" instructions are handled separately. --auto-litpools | --no-auto-litpools Control the treatment of literal pools. The default is --no-auto-litpools, which in the absence of --text-section-literals places literals in separate sections in the output file. This allows the literal pool to be placed in a data RAM/ROM. With --auto-litpools, the literals are interspersed in the text section in order to keep them as close as possible to their references, explicit ".literal_position" directives are not required. This may be necessary for very large functions, where single literal pool at the beginning of the function may not be reachable by "L32R" instructions at the end. These options only affect literals referenced via PC-relative "L32R" instructions; literals for absolute mode "L32R" instructions are handled separately. When used together with --text-section-literals, --auto-litpools takes precedence. --absolute-literals | --no-absolute-literals Indicate to the assembler whether "L32R" instructions use absolute or PC-relative addressing. If the processor includes the absolute addressing option, the default is to use absolute "L32R" relocations. Otherwise, only the PC- relative "L32R" relocations can be used. --target-align | --no-target-align Enable or disable automatic alignment to reduce branch penalties at some expense in code size. This optimization is enabled by default. Note that the assembler will always align instructions like "LOOP" that have fixed alignment requirements. --longcalls | --no-longcalls Enable or disable transformation of call instructions to allow calls across a greater range of addresses. This option should be used when call targets can potentially be out of range. It may degrade both code size and performance, but the linker can generally optimize away the unnecessary overhead when a call ends up within range. The default is --no-longcalls. --transform | --no-transform Enable or disable all assembler transformations of Xtensa instructions, including both relaxation and optimization. The default is --transform; --no-transform should only be used in the rare cases when the instructions must be exactly as specified in the assembly source. Using --no-transform causes out of range instruction operands to be errors. --rename-section oldname=newname Rename the oldname section to newname. This option can be used multiple times to rename multiple sections. --trampolines | --no-trampolines Enable or disable transformation of jump instructions to allow jumps across a greater range of addresses. This option should be used when jump targets can potentially be out of range. In the absence of such jumps this option does not affect code size or performance. The default is --trampolines. --abi-windowed | --abi-call0 Choose ABI tag written to the ".xtensa.info" section. ABI tag indicates ABI of the assembly code. A warning is issued by the linker on an attempt to link object files with inconsistent ABI tags. Default ABI is chosen by the Xtensa core configuration. The following options are available when as is configured for an Z80 processor. @chapter Z80 Dependent Features Command-line Options -march=CPU[-EXT...][+EXT...] This option specifies the target processor. The assembler will issue an error message if an attempt is made to assemble an instruction which will not execute on the target processor. The following processor names are recognized: "z80", "z180", "ez80", "gbz80", "z80n", "r800". In addition to the basic instruction set, the assembler can be told to accept some extention mnemonics. For example, "-march=z180+sli+infc" extends z180 with SLI instructions and IN F,(C). The following extentions are currently supported: "full" (all known instructions), "adl" (ADL CPU mode by default, eZ80 only), "sli" (instruction known as SLI, SLL or SL1), "xyhl" (instructions with halves of index registers: IXL, IXH, IYL, IYH), "xdcb" (instructions like RotOp (II+d),R and BitOp n,(II+d),R), "infc" (instruction IN F,(C) or IN (C)), "outc0" (instruction OUT (C),0). Note that rather than extending a basic instruction set, the extention mnemonics starting with "-" revoke the respective functionality: "-march=z80-full+xyhl" first removes all default extentions and adds support for index registers halves only. If this option is not specified then "-march=z80+xyhl+infc" is assumed. -local-prefix=prefix Mark all labels with specified prefix as local. But such label can be marked global explicitly in the code. This option do not change default local label prefix ".L", it is just adds new one. -colonless Accept colonless labels. All symbols at line begin are treated as labels. -sdcc Accept assembler code produced by SDCC. -fp-s=FORMAT Single precision floating point numbers format. Default: ieee754 (32 bit). -fp-d=FORMAT Double precision floating point numbers format. Default: ieee754 (64 bit). SEE ALSO top gcc(1), ld(1), and the Info entries for binutils and ld. COPYRIGHT top Copyright (c) 1991-2023 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". COLOPHON top This page is part of the binutils (a collection of tools for working with executable binaries) project. Information about the project can be found at http://www.gnu.org/software/binutils/. If you have a bug report for this manual page, see http://sourceware.org/bugzilla/enter_bug.cgi?product=binutils. This page was obtained from the tarball binutils-2.41.tar.gz fetched from https://ftp.gnu.org/gnu/binutils/ on 2023-12-22. If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org binutils-2.41 2023-12-22 AS(1) Pages that refer to this page: elf(5) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # as\n\n> Portable GNU assembler.\n> Primarily intended to assemble output from `gcc` to be used by `ld`.\n> More information: <https://manned.org/as>.\n\n- Assemble a file, writing the output to `a.out`:\n\n`as {{file.s}}`\n\n- Assemble the output to a given file:\n\n`as {{file.s}} -o {{out.o}}`\n\n- Generate output faster by skipping whitespace and comment preprocessing. (Should only be used for trusted compilers):\n\n`as -f {{file.s}}`\n\n- Include a given path to the list of directories to search for files specified in `.include` directives:\n\n`as -I {{path/to/directory}} {{file.s}}`\n |
at | at(1p) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training at(1p) Linux manual page PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT AT(1P) POSIX Programmer's Manual AT(1P) PROLOG top This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME top at execute commands at a later time SYNOPSIS top at [-m] [-f file] [-q queuename] -t time_arg at [-m] [-f file] [-q queuename] timespec... at -r at_job_id... at -l -q queuename at -l [at_job_id...] DESCRIPTION top The at utility shall read commands from standard input and group them together as an at-job, to be executed at a later time. The at-job shall be executed in a separate invocation of the shell, running in a separate process group with no controlling terminal, except that the environment variables, current working directory, file creation mask, and other implementation-defined execution-time attributes in effect when the at utility is executed shall be retained and used when the at-job is executed. When the at-job is submitted, the at_job_id and scheduled time shall be written to standard error. The at_job_id is an identifier that shall be a string consisting solely of alphanumeric characters and the <period> character. The at_job_id shall be assigned by the system when the job is scheduled such that it uniquely identifies a particular job. User notification and the processing of the job's standard output and standard error are described under the -m option. Users shall be permitted to use at if their name appears in the file at.allow which is located in an implementation-defined directory. If that file does not exist, the file at.deny, which is located in an implementation-defined directory, shall be checked to determine whether the user shall be denied access to at. If neither file exists, only a process with appropriate privileges shall be allowed to submit a job. If only at.deny exists and is empty, global usage shall be permitted. The at.allow and at.deny files shall consist of one user name per line. OPTIONS top The at utility shall conform to the Base Definitions volume of POSIX.12017, Section 12.2, Utility Syntax Guidelines. The following options shall be supported: -f file Specify the pathname of a file to be used as the source of the at-job, instead of standard input. -l (The letter ell.) Report all jobs scheduled for the invoking user if no at_job_id operands are specified. If at_job_ids are specified, report only information for these jobs. The output shall be written to standard output. -m Send mail to the invoking user after the at-job has run, announcing its completion. Standard output and standard error produced by the at-job shall be mailed to the user as well, unless redirected elsewhere. Mail shall be sent even if the job produces no output. If -m is not used, the job's standard output and standard error shall be provided to the user by means of mail, unless they are redirected elsewhere; if there is no such output to provide, the implementation need not notify the user of the job's completion. -q queuename Specify in which queue to schedule a job for submission. When used with the -l option, limit the search to that particular queue. By default, at-jobs shall be scheduled in queue a. In contrast, queue b shall be reserved for batch jobs; see batch. The meanings of all other queuenames are implementation- defined. If -q is specified along with either of the -t time_arg or timespec arguments, the results are unspecified. -r Remove the jobs with the specified at_job_id operands that were previously scheduled by the at utility. -t time_arg Submit the job to be run at the time specified by the time option-argument, which the application shall ensure has the format as specified by the touch -t time utility. OPERANDS top The following operands shall be supported: at_job_id The name reported by a previous invocation of the at utility at the time the job was scheduled. timespec Submit the job to be run at the date and time specified. All of the timespec operands are interpreted as if they were separated by <space> characters and concatenated, and shall be parsed as described in the grammar at the end of this section. The date and time shall be interpreted as being in the timezone of the user (as determined by the TZ variable), unless a timezone name appears as part of time, below. In the POSIX locale, the following describes the three parts of the time specification string. All of the values from the LC_TIME categories in the POSIX locale shall be recognized in a case-insensitive manner. time The time can be specified as one, two, or four digits. One-digit and two-digit numbers shall be taken to be hours; four-digit numbers to be hours and minutes. The time can alternatively be specified as two numbers separated by a <colon>, meaning hour:minute. An AM/PM indication (one of the values from the am_pm keywords in the LC_TIME locale category) can follow the time; otherwise, a 24-hour clock time shall be understood. A timezone name can also follow to further qualify the time. The acceptable timezone names are implementation-defined, except that they shall be case-insensitive and the string utc is supported to indicate the time is in Coordinated Universal Time. In the POSIX locale, the time field can also be one of the following tokens: midnight Indicates the time 12:00 am (00:00). noon Indicates the time 12:00 pm. now Indicates the current day and time. Invoking at <now> shall submit an at-job for potentially immediate execution (that is, subject only to unspecified scheduling delays). date An optional date can be specified as either a month name (one of the values from the mon or abmon keywords in the LC_TIME locale category) followed by a day number (and possibly year number preceded by a comma), or a day of the week (one of the values from the day or abday keywords in the LC_TIME locale category). In the POSIX locale, two special days shall be recognized: today Indicates the current day. tomorrow Indicates the day following the current day. If no date is given, today shall be assumed if the given time is greater than the current time, and tomorrow shall be assumed if it is less. If the given month is less than the current month (and no year is given), next year shall be assumed. increment The optional increment shall be a number preceded by a <plus-sign> ('+') and suffixed by one of the following: minutes, hours, days, weeks, months, or years. (The singular forms shall also be accepted.) The keyword next shall be equivalent to an increment number of +1. For example, the following are equivalent commands: at 2pm + 1 week at 2pm next week The following grammar describes the precise format of timespec in the POSIX locale. The general conventions for this style of grammar are described in Section 1.3, Grammar Conventions. This formal syntax shall take precedence over the preceding text syntax description. The longest possible token or delimiter shall be recognized at a given point. When used in a timespec, white space shall also delimit tokens. %token hr24clock_hr_min %token hr24clock_hour /* An hr24clock_hr_min is a one, two, or four-digit number. A one-digit or two-digit number constitutes an hr24clock_hour. An hr24clock_hour may be any of the single digits [0,9], or may be double digits, ranging from [00,23]. If an hr24clock_hr_min is a four-digit number, the first two digits shall be a valid hr24clock_hour, while the last two represent the number of minutes, from [00,59]. */ %token wallclock_hr_min %token wallclock_hour /* A wallclock_hr_min is a one, two-digit, or four-digit number. A one-digit or two-digit number constitutes a wallclock_hour. A wallclock_hour may be any of the single digits [1,9], or may be double digits, ranging from [01,12]. If a wallclock_hr_min is a four-digit number, the first two digits shall be a valid wallclock_hour, while the last two represent the number of minutes, from [00,59]. */ %token minute /* A minute is a one or two-digit number whose value can be [0,9] or [00,59]. */ %token day_number /* A day_number is a number in the range appropriate for the particular month and year specified by month_name and year_number, respectively. If no year_number is given, the current year is assumed if the given date and time are later this year. If no year_number is given and the date and time have already occurred this year and the month is not the current month, next year is the assumed year. */ %token year_number /* A year_number is a four-digit number representing the year A.D., in which the at_job is to be run. */ %token inc_number /* The inc_number is the number of times the succeeding increment period is to be added to the specified date and time. */ %token timezone_name /* The name of an optional timezone suffix to the time field, in an implementation-defined format. */ %token month_name /* One of the values from the mon or abmon keywords in the LC_TIME locale category. */ %token day_of_week /* One of the values from the day or abday keywords in the LC_TIME locale category. */ %token am_pm /* One of the values from the am_pm keyword in the LC_TIME locale category. */ %start timespec %% timespec : time | time date | time increment | time date increment | nowspec ; nowspec : "now" | "now" increment ; time : hr24clock_hr_min | hr24clock_hr_min timezone_name | hr24clock_hour ":" minute | hr24clock_hour ":" minute timezone_name | wallclock_hr_min am_pm | wallclock_hr_min am_pm timezone_name | wallclock_hour ":" minute am_pm | wallclock_hour ":" minute am_pm timezone_name | "noon" | "midnight" ; date : month_name day_number | month_name day_number "," year_number | day_of_week | "today" | "tomorrow" ; increment : "+" inc_number inc_period | "next" inc_period ; inc_period : "minute" | "minutes" | "hour" | "hours" | "day" | "days" | "week" | "weeks" | "month" | "months" | "year" | "years" ; STDIN top The standard input shall be a text file consisting of commands acceptable to the shell command language described in Chapter 2, Shell Command Language. The standard input shall only be used if no -f file option is specified. INPUT FILES top See the STDIN section. The text files at.allow and at.deny, which are located in an implementation-defined directory, shall contain zero or more user names, one per line, of users who are, respectively, authorized or denied access to the at and batch utilities. ENVIRONMENT VARIABLES top The following environment variables shall affect the execution of at: LANG Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.12017, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) LC_ALL If set to a non-empty string value, override the values of all the other internationalization variables. LC_CTYPE Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments and input files). LC_MESSAGES Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error and informative messages written to standard output. NLSPATH Determine the location of message catalogs for the processing of LC_MESSAGES. LC_TIME Determine the format and contents for date and time strings written and accepted by at. SHELL Determine a name of a command interpreter to be used to invoke the at-job. If the variable is unset or null, sh shall be used. If it is set to a value other than a name for sh, the implementation shall do one of the following: use that shell; use sh; use the login shell from the user database; or any of the preceding accompanied by a warning diagnostic about which was chosen. TZ Determine the timezone. The job shall be submitted for execution at the time specified by timespec or -t time relative to the timezone specified by the TZ variable. If timespec specifies a timezone, it shall override TZ. If timespec does not specify a timezone and TZ is unset or null, an unspecified default timezone shall be used. ASYNCHRONOUS EVENTS top Default. STDOUT top When standard input is a terminal, prompts of unspecified format for each line of the user input described in the STDIN section may be written to standard output. In the POSIX locale, the following shall be written to the standard output for each job when jobs are listed in response to the -l option: "%s\t%s\n", at_job_id, <date> where date shall be equivalent in format to the output of: date +"%a %b %e %T %Y" The date and time written shall be adjusted so that they appear in the timezone of the user (as determined by the TZ variable). STDERR top In the POSIX locale, the following shall be written to standard error when a job has been successfully submitted: "job %s at %s\n", at_job_id, <date> where date has the same format as that described in the STDOUT section. Neither this, nor warning messages concerning the selection of the command interpreter, shall be considered a diagnostic that changes the exit status. Diagnostic messages, if any, shall be written to standard error. OUTPUT FILES top None. EXTENDED DESCRIPTION top None. EXIT STATUS top The following exit values shall be returned: 0 The at utility successfully submitted, removed, or listed a job or jobs. >0 An error occurred. CONSEQUENCES OF ERRORS top The job shall not be scheduled, removed, or listed. The following sections are informative. APPLICATION USAGE top The format of the at command line shown here is guaranteed only for the POSIX locale. Other cultures may be supported with substantially different interfaces, although implementations are encouraged to provide comparable levels of functionality. Since the commands run in a separate shell invocation, running in a separate process group with no controlling terminal, open file descriptors, traps, and priority inherited from the invoking environment are lost. Some implementations do not allow substitution of different shells using SHELL. System V systems, for example, have used the login shell value for the user in /etc/passwd. To select reliably another command interpreter, the user must include it as part of the script, such as: $ at 1800 myshell myscript EOT job ... at ... $ EXAMPLES top 1. This sequence can be used at a terminal: at -m 0730 tomorrow sort < file >outfile EOT 2. This sequence, which demonstrates redirecting standard error to a pipe, is useful in a command procedure (the sequence of output redirection specifications is significant): at now + 1 hour <<! diff file1 file2 2>&1 >outfile | mailx mygroup ! 3. To have a job reschedule itself, at can be invoked from within the at-job. For example, this daily processing script named my.daily runs every day (although crontab is a more appropriate vehicle for such work): # my.daily runs every day daily processing at now tomorrow < my.daily 4. The spacing of the three portions of the POSIX locale timespec is quite flexible as long as there are no ambiguities. Examples of various times and operand presentation include: at 0815am Jan 24 at 8 :15amjan24 at now "+ 1day" at 5 pm FRIday at '17 utc+ 30minutes' RATIONALE top The at utility reads from standard input the commands to be executed at a later time. It may be useful to redirect standard output and standard error within the specified commands. The -t time option was added as a new capability to support an internationalized way of specifying a time for execution of the submitted job. Early proposals added a ``jobname'' concept as a way of giving submitted jobs names that are meaningful to the user submitting them. The historical, system-specified at_job_id gives no indication of what the job is. Upon further reflection, it was decided that the benefit of this was not worth the change in historical interface. The at functionality is useful in simple environments, but in large or complex situations, the functionality provided by the Batch Services option is more suitable. The -q option historically has been an undocumented option, used mainly by the batch utility. The System V -m option was added to provide a method for informing users that an at-job had completed. Otherwise, users are only informed when output to standard error or standard output are not redirected. The behavior of at <now> was changed in an early proposal from being unspecified to submitting a job for potentially immediate execution. Historical BSD at implementations support this. Historical System V implementations give an error in that case, but a change to the System V versions should have no backwards- compatibility ramifications. On BSD-based systems, a -u user option has allowed those with appropriate privileges to access the work of other users. Since this is primarily a system administration feature and is not universally implemented, it has been omitted. Similarly, a specification for the output format for a user with appropriate privileges viewing the queues of other users has been omitted. The -f file option from System V is used instead of the BSD method of using the last operand as the pathname. The BSD method is ambiguousdoes: at 1200 friday mean the same thing if there is a file named friday in the current directory? The at_job_id is composed of a limited character set in historical practice, and it is mandated here to invalidate systems that might try using characters that require shell quoting or that could not be easily parsed by shell scripts. The at utility varies between System V and BSD systems in the way timezones are used. On System V systems, the TZ variable affects the at-job submission times and the times displayed for the user. On BSD systems, TZ is not taken into account. The BSD behavior is easily achieved with the current specification. If the user wishes to have the timezone default to that of the system, they merely need to issue the at command immediately following an unsetting or null assignment to TZ. For example: TZ= at noon ... gives the desired BSD result. While the yacc-like grammar specified in the OPERANDS section is lexically unambiguous with respect to the digit strings, a lexical analyzer would probably be written to look for and return digit strings in those cases. The parser could then check whether the digit string returned is a valid day_number, year_number, and so on, based on the context. FUTURE DIRECTIONS top None. SEE ALSO top batch(1p), crontab(1p) The Base Definitions volume of POSIX.12017, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines COPYRIGHT top Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . IEEE/The Open Group 2017 AT(1P) Pages that refer to this page: batch(1p), crontab(1p) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # at\n\n> Executes commands at a specified time.\n> More information: <https://man.archlinux.org/man/at.1>.\n\n- Open an `at` prompt to create a new set of scheduled commands, press `Ctrl + D` to save and exit:\n\n`at {{hh:mm}}`\n\n- Execute the commands and email the result using a local mailing program such as Sendmail:\n\n`at {{hh:mm}} -m`\n\n- Execute a script at the given time:\n\n`at {{hh:mm}} -f {{path/to/file}}`\n\n- Display a system notification at 11pm on February 18th:\n\n`echo "notify-send '{{Wake up!}}'" | at {{11pm}} {{Feb 18}}`\n |
auditd | auditd(8) - Linux manual page man7.org > Linux > man-pages Linux/UNIX system programming training auditd(8) Linux manual page NAME | SYNOPSIS | DESCRIPTION | OPTIONS | SIGNALS | EXIT CODES | FILES | NOTES | SEE ALSO | AUTHOR | COLOPHON AUDITD(8) System Administration Utilities AUDITD(8) NAME top auditd - The Linux Audit daemon SYNOPSIS top auditd [-f] [-l] [-n] [-s disable|enable|nochange] [-c <config_dir>] DESCRIPTION top auditd is the userspace component to the Linux Auditing System. It's responsible for writing audit records to the disk. Viewing the logs is done with the ausearch or aureport utilities. Configuring the audit system or loading rules is done with the auditctl utility. During startup, the rules in /etc/audit/audit.rules are read by auditctl and loaded into the kernel. Alternately, there is also an augenrules program that reads rules located in /etc/audit/rules.d/ and compiles them into an audit.rules file. The audit daemon itself has some configuration options that the admin may wish to customize. They are found in the auditd.conf file. OPTIONS top -f leave the audit daemon in the foreground for debugging. Messages also go to stderr rather than the audit log. -l allow the audit daemon to follow symlinks for config files. -n no fork. This is useful for running off of inittab or systemd. -s=ENABLE_STATE specify when starting if auditd should change the current value for the kernel enabled flag. Valid values for ENABLE_STATE are "disable", "enable" or "nochange". The default is to enable (and disable when auditd terminates). The value of the enabled flag may be changed during the lifetime of auditd using 'auditctl -e'. -c Specify alternate config file directory. Note that this same directory will be passed to the dispatcher. (default: /etc/audit/) SIGNALS top SIGHUP causes auditd to reconfigure. This means that auditd re- reads the configuration file. If there are no syntax errors, it will proceed to implement the requested changes. If the reconfigure is successful, a DAEMON_CONFIG event is recorded in the logs. If not successful, error handling is controlled by space_left_action, admin_space_left_action, disk_full_action, and disk_error_action parameters in auditd.conf. SIGTERM caused auditd to discontinue processing audit events, write a shutdown audit event, and exit. SIGUSR1 causes auditd to immediately rotate the logs. It will consult the max_log_file_action to see if it should keep the logs or not. SIGUSR2 causes auditd to attempt to resume logging and passing events to plugins. This is usually needed after logging has been suspended or the internal queue is overflowed. Either of these conditions depends on the applicable configuration settings. SIGCONT causes auditd to dump a report of internal state to /var/run/auditd.state. EXIT CODES top 1 Cannot adjust priority, daemonize, open audit netlink, write the pid file, start up plugins, resolve the machine name, set audit pid, or other initialization tasks. 2 Invalid or excessive command line arguments 4 The audit daemon doesn't have sufficient privilege 6 There is an error in the configuration file FILES top /etc/audit/auditd.conf - configuration file for audit daemon /etc/audit/audit.rules - audit rules to be loaded at startup /etc/audit/rules.d/ - directory holding individual sets of rules to be compiled into one file by augenrules. /etc/audit/plugins.d/ - directory holding individual plugin configuration files. /etc/audit/audit-stop - These rules are loaded when the audit daemon stops. /var/run/auditd.state - report about internal state. NOTES top A boot param of audit=1 should be added to ensure that all processes that run before the audit daemon starts is marked as auditable by the kernel. Not doing that will make a few processes impossible to properly audit. The audit daemon can receive audit events from other audit daemons via the audisp-remote plugin. The audit daemon may be linked with tcp_wrappers to control which machines can connect. If this is the case, you can add an entry to hosts.allow and deny. SEE ALSO top auditd.conf(5), auditd-plugins(5), ausearch(8), aureport(8), auditctl(8), augenrules(8), audit.rules(7). AUTHOR top Steve Grubb COLOPHON top This page is part of the audit (Linux Audit) project. Information about the project can be found at http://people.redhat.com/sgrubb/audit/. If you have a bug report for this manual page, send it to linux-audit@redhat.com. This page was obtained from the project's upstream Git repository https://github.com/linux-audit/audit-userspace.git on 2023-12-22. (At that time, the date of the most recent commit that was found in the repository was 2023-11-30.) If you discover any rendering problems in this HTML version of the page, or you believe there is a better or more up-to-date source for the page, or you have corrections or improvements to the information in this COLOPHON (which is not part of the original manual page), send a mail to man-pages@man7.org Red Hat Sept 2021 AUDITD(8) Pages that refer to this page: audit_request_status(3), audit_set_backlog_limit(3), audit_set_backlog_wait_time(3), audit_set_enabled(3), audit_set_failure(3), audit_set_pid(3), audit_set_rate_limit(3), get_auditfail_action(3), set_aumessage_mode(3), auditd.conf(5), auditd-plugins(5), zos-remote.conf(5), audit.rules(7), audispd-zos-remote(8), auditctl(8), augenrules(8), aureport(8), ausearch(8), pam_loginuid(8), systemd-update-utmp.service(8) HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. | # auditd\n\n> This responds to requests from the audit utility and notifications from the kernel.\n> It should not be invoked manually.\n> More information: <https://manned.org/auditd>.\n\n- Start the daemon:\n\n`auditd`\n\n- Start the daemon in debug mode:\n\n`auditd -d`\n\n- Start the daemon on-demand from launchd:\n\n`auditd -l`\n |
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