AR(1)

📦
version 2.47 · 6 versions
, in ubuntu stonking

💖 AR(1) — GNU Development Tools ✨

okay bestie, pull up a chair because we're about to talk about ar, and honestly? she's lowkey the backbone of half your toolchain and nobody ever gives her her flowers. this is the GNU Development Tools manual, page AR(1), and yes we're doing this properly. grab a snack. 🍓

🌸 NAME

ar — create, modify, and extract from archives

🦋 SYNOPSIS

ar [-X32_64]
   [-]p[mod]
   [--plugin name]
   [--target bfdname]
   [--output dirname]
   [--record-libdeps libdeps]
   [--thin]
   [relpos] [count] archive [member...]
ar -M [< mri-script]

👑 DESCRIPTION

so the GNU ar program does three iconic things: it creates, it modifies, and it extracts from archives. and what is an archive, you ask? it's one single file that holds a whole collection of other files, all arranged in a structure that lets you get the original individual files back out. those individual files?) they're called the members of the archive. periodt. 💅

here's the cute part: the original files' contents, mode (permissions), timestamp, owner, and group are all preserved inside the archive, and can be restored when you extract. nothing gets lost. she remembers everything. 💖

GNU ar can maintain archives whose members have names of any length. however — and this is the fine print — depending on how ar is configured on your system, a limit on member-name length may be imposed, for compatibility with archive formats maintained by other tools. if that limit exists, it's often 15 characters (typical of formats related to a.out) or 16 characters (typical of formats related to coff). iykyk. 🙈

ar is considered a binary utility, because archives of this sort are most often used as libraries holding commonly needed subroutines. and since libraries often depend on other libraries, ar can also record the dependencies of a library — but only when you specify the --record-libdeps option. noted. ✨

now, when you specify the modifier s, ar creates an index to the symbols defined in relocatable object modules in the archive. once that index exists, it gets updated in the archive whenever ar makes a change to its contents — save for the q update operation. and an archive with such an index? it speeds up linking to the library. main character energy, honestly. ⭐

you can use nm -s or nm --print-armap to list this index table. and 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. she's efficient like that. 💅

💀 important: 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. no take-backs.

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. 🌈

and the paths to the elements of the archive are stored relative to the archive itself. okay? iconic.

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.

either way she's serving. 🫶

✨ OPTIONS ✨

GNU ar lets you mix the operation code p and modifier flags mod in any order, within the first command-line argument. do whatever feels right bestie. 💅

and if you wish, you may begin the first command-line argument with a dash. optional dash. she's flexible.

🎀 the operation keyletter p

the p keyletter specifies what operation to execute. it may be any of the following — but you must specify only one of them. pick a lane, babe:

  • d — Delete modules from the archive. specify the names of the modules to be deleted as member...; the archive is left untouched if you specify no files to delete. and 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 genuinely make a difference in how programs are linked using the library, if a symbol is defined in more than one member. so like, it matters!! 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. and 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 whole point of this operation is speed, implementations of ar have the option of not updating the archive's symbol table if one exists. however — too many different systems 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, because it's possible to use it as either a command or a modifier. either way it does the same thing. she contains multitudes. 💅
  • 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. and heads up: if there is more than one file with the same name (say, fie) in an archive (say b.a), then 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. 🎁
careful bestie: 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 use the --output option to specify an output directory.

💜 the modifiers mod

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. she just wants a heads up. 🥺
  • 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, which will cause it to create archives that 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

...and that thought finishes up in part 2, bestie — don't go anywhere 💖

ar rcST archive.a subdir/file1 subdir/file2 file1

and here's the tea bestie: that first "subdir/file1" is gonna get replaced with "file1" from your current directory. Adding P stops that from happening. 🛑

  • s — writes an object-file index into the archive, or updates one that's already there, even if nothing else changed in the archive. You can run this modifier with any operation, or all by itself. Running ar s on an archive is literally the same thing as running ranlib on it. ✨
  • S — do not generate an archive symbol table. This can speed up building a big library in several steps, but it will negatively impact performance if you use the resulting archive with the linker. To actually get a symbol table, you have to omit the S modifier on the last execution of ar, or you have to run ranlib on the archive yourself. 💅
  • T — deprecated alias for --thin. T is not recommended, because in many ar implementations T means something completely different, as specified by X/Open System Interface. So like, don't. 🙈
  • u — normally ar r... inserts all the files you listed into the archive. If you only want to insert the ones that are newer than existing members with the same names, use this modifier. The u modifier is only allowed for the r (replace) operation. In particular, the combination qu is not allowed, since checking the timestamps would lose any speed advantage you get from q.

Note — if an archive has been created in a deterministic manner, e.g. via the use of the D modifier, then replacement will always happen and the u modifier will be ineffective. 😭

  • 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. Lots of operations display extra info, like which filenames were processed, when you append v. 👑
  • 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
okay so the manpage genuinely just stops right there after "See" — that's it, that's the sentence. Not me, the source did that. 😭
  • --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 an 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 🌈

nm(1), ranlib(1), and the Info entries for binutils.

Copyright (c) 1991-2026 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".

and that's the whole page, bestie, we made it to the end 🎉 this lil masterpiece is from binutils-2.47, dated 2026-09-12, and it lives in section AR(1) — iconic behavior fr fr, go archive something and slay 💅✨🦋

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