AR(1)

AR(1) 💖 GNU Development Tools

okay bestie, sit down, hydrate, because we're about to talk about ar — the GNU Development Tools girlie who creates, modifies, and extracts from archives. yes THAT ar. the one your linker is lowkey obsessed with. let's go 🫶

✨ 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 creates, modifies, and extracts from archives. and what even IS an archive? it's a single file that's holding a whole collection of other files in a structure that makes it possible to retrieve the original individual files back out again — those individual files are called members of the archive. it's giving "one girl, many personalities, but in file format" 💅

the original files' contents, mode (permissions), timestamp, owner, and group are all preserved inside the archive, and they can be restored on extraction. no cap, it remembers everything about them. it's a keeper.

GNU ar can maintain archives whose members have names of any length — iconic. BUT, 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 that limit exists, it's often 15 characters (typical of formats related to a.out) or 16 characters (typical of formats related to coff). so like, know your limits bestie.

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 when the --record-libdeps option is specified. depend on each other? we been knew, that's the whole friend group dynamic.

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 — we'll get to that, she's the exception 🙈). an archive with such an index speeds up linking to the library. slay.

you may 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. she's a specialist. she does one thing and she does it well.

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. thin archive said "why would I duplicate you when I can just point at you" — minimal effort, maximum results, truly the mood ✨

an archive can either be thin or it can be normal. it cannot be both at the same time. and once an archive is created, its format cannot be changed without first deleting it and then creating a new archive in its place. so choose wisely, bestie, that's a commitment fr fr 😭

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. no nesting dolls here, we're all on the same level 💅

the paths to the elements of the archive are stored relative to the archive itself. note that down.

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. two ways to run the same queen. pick your vibe. 👑

🎀 OPTIONS 🎀

GNU ar allows you to mix the operation code p and modifier flags mod in any order, within the first command-line argument. any order!! we love flexibility!!

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

🌈 the operation letters (`p`)

the p keyletter specifies what operation to execute; it may be any of the following, but you must specify only one of them. ONE. not two. one. 🙅

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. so you can watch her work 💅
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. so order matters, bestie, it's giving seating chart drama. 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. plot twist ✨
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. no half-done chaos here, she's respectful. 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. 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), 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. but — 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. (yes, the original says "then used the" — we're keeping it, character for character, because facts are facts 🫶)

🦋 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. so like, announce your intentions bestie, don't just show 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. reproducibility queen 👑 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. trade-off vibes 💅
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". one argument, bestie, don't split them up 🙈
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. for when "which one?" has an actual answer.
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. glow-up or time capsule, your call ✨
O — Display member offsets inside the archive. use together with the t option. team work makes the dream work.
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's exactly where part 1 stops, bestie — she left us mid-sentence, which is honestly so on brand 👀 part 2 is coming, don't go anywhere 💖

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

...and the tea is that the first subdir/file1 gets swapped out for file1 straight from whatever directory you're standing in rn. Add P to that and the replacement just... doesn't happen. protected. 💅

s — writes an object-file index into the archive, or refreshes one that's already there, even if literally nothing else about the archive changed. You can run this with any operation, or all by itself, your call. Running ar s on an archive hits exactly the same as running ranlib on it. twin behavior, no cap. ✨
S — do not make an archive symbol table. This can make building a big library in multiple steps faster, but it will lowkey hurt you later if the archive gets used with the linker. To actually get a symbol table you either leave off the S modifier on the last time you run ar, or you run ranlib on the archive. pick your fighter 🫶
T — deprecated alias for --thin. Do not use T, bestie, it's giving risky: in so many ar implementations T means something completely different, as laid out by X/Open System Interface. deprecated = dead to me 💀
u — normally ar r... inserts every single file you listed into the archive. If you only want the ones that are newer than the existing members with the same names, use this modifier. u is only allowed with the r (replace) operation. Specifically, qu together is not allowed, because checking timestamps would kill the whole speed advantage you get from q. 😤

Heads up — if an archive was created deterministically, like via the D modifier, then replacement will always happen and the u modifier does absolutely nothing. ineffective, embarrassed, going home.

U — do not operate in deterministic mode. It's the inverse of the D modifier up above: added files and the archive index get their actual UID, GID, timestamp, and file mode values. 🌈

This is the default unless binutils was configured with --enable-deterministic-archives.

v — the verbose version of an operation, please. Lots of operations spill extra info when v is tacked on — filenames processed, that kind of thing. main character energy for your terminal output 👑
V — shows the version number of ar. that's it. that's the whole job. ⭐

The ar program also supports some command-line options that are neither modifiers nor actions, but which do change how it behaves in specific ways. special little guys:

--help — displays the list of command-line options that ar supports, then dips. ✌️
--version — displays the version info for ar, then dips.
-X32_64 — ar straight up ignores an initial option spelled -X32_64, for compatibility with AIX. The behavior this option produces 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 makes ar 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 was built with plugin support enabled.

If --plugin isn't 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 gets used.

Please note that this plugin search directory is not the one used by ld's -plugin option. To make ar use the linker plugin, it has to 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's called LLVMgold.so. The GCC plugin is always backwards compatible with earlier versions, so copying just the newest one is enough. 💖

--target target — the optional command-line switch --target bfdname says that the archive members are in an object code format different from your system's default format. See
--output dirname — the --output option specifies a path to a directory that archive members should be extracted into. If it's not specified, the current directory gets used. 🎀

Note — even though the presence of this option does imply an x extraction operation, that option still has to be included on the command line. no skipping steps bestie.

--record-libdeps libdeps — the --record-libdeps option is identical to the l modifier, just handled in long form.
--thin — makes the specified archive a thin archive. If it already exists and is a regular archive, the existing members have to be present in the same directory as archive.
@file — reads command-line options from file. The options read get inserted in place of the original @file option. If file doesn't exist, or can't be read, then the option is treated literally, and not removed. 😭

Options inside file are separated by whitespace. A whitespace character can be included in an option by wrapping the whole option in either single or double quotes. Any character (backslash included) can be included by prefixing the character to be included with a backslash. The file may itself contain additional @file options; any such options get processed recursively. 🦋

🌸 SEE ALSO 🌸

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

💜 COPYRIGHT 💜

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 🫶 this one's from binutils-2.47, dated 2026-08-11, and honestly? iconic. go archive something. 💅✨

📦 where this page comes from

arch rolling: binutils 2.47-4 · GPL-2.0-or-later AND GPL-3.0-or-later AND LGPL-2.0-or-later AND LGPL-3.0-or-later AND GFDL-1.3 AND FSFAP
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-10-13: a language model's rewrite of the original, under its terms