AR(1)

📦 version 12.2.0, in nixpkgs unstable

💖 AR(1) — GNU Development Tools archive energy 💖

okay so bestie, this is the GNU Development Tools manual page for ar, and it is literally the archive girlie of your Unix toolbox.

🌸 NAME 🌸

ar — create, modify, and extract from archives. That's the whole vibe. 💅

✨ SYNOPSIS ✨

ar [-X32_64] [-]p[mod] [--plugin name] [--target bfdname] [relpos]
[count] archive [member...]

🎀 DESCRIPTION 🎀

Okay so 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. No cap.

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. Iconic behavior, honestly.

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. Highkey efficient.

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. So choose your fighter, bestie. ⚔️

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 way that works is very "no nesting, just vibes."

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. Two modes, one icon. 👑

💅 OPTIONS 💅

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. Slay, flexible.

The p keyletter specifies what operation to execute; it may be any of the following, but you must specify only one of them:

🕹️ the p keyletter operations

  • 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; if you also want to see the modes (permissions), timestamp, owner, group, and size, you can request that by also specifying the v modifier.
    • 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.
🚨 Warning: Files cannot be extracted from a thin archive. Periodt.

🧚 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. 🐣
  • 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 — This modifier is accepted but not used. She's just here for the vibes. 💀
  • 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. 🕰️
  • P — Use the full path name when matching names in the archive. GNU ar can not create an archive with a full path name (such archives are not POSIX complaint), but other archive creators can. This option will cause GNU ar to match file names using a complete path name, which can be convenient when extracting a single file from an archive created by another tool. 🛤️
  • 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 — 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. 🦋
  • u — okay so normally ar r... just shoves every file you list into the archive, no questions asked. But if you only want the ones that are newer than the members already chilling there under the same name? That's this modifier, bestie 💅. Heads up though: u is only allowed for the r (replace) operation. So the combo qu? Literally not allowed — because timestamp-checking would eat up all the speed you got from q, and what's the point then 😭.
  • U — do not operate in deterministic mode. It's the exact inverse of the D modifier up above: files you add, and the archive index itself, get their actual UID, GID, timestamp, and file mode values. No cosplay, just real ones ✨.

This one's the default — unless binutils was configured with --enable-deterministic-archives, in which case, well, it isn't 🙈.

  • v — the verbose version of an operation, queen of receipts 👑. Lots of operations will show you extra info (filenames processed, that kind of thing) when you tack v on the end.
  • V — shows the version number of ar. That's it. That's the whole vibe 🎀.

The ar program is also out here supporting some command line options that are neither modifiers nor actions, but which do change how it behaves in specific ways. Iconic of it, honestly:

  • --help — displays the list of command line options that ar supports, then dips. ✌️
  • --version — displays the version information of ar, then dips. Same energy.
  • -X32_64 — ar ignores an initial option spelt -X32_64, purely for compatibility with AIX. The behaviour this option produces is already the default for GNU ar, so like… nothing happens, and that's on purpose 💀. ar does not support any of the other -X options — in particular, it does not support -X32, which is the default for AIX ar. So don't come at it with AIX expectations, bestie.
  • --plugin name — this 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 🔥.

Just so you know: this option is only available if the toolchain has been built with plugin support enabled. No plugin support, no plugin option, no cap 🧢.

And 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. First come, first served, main character energy ⭐.

Please note: this plugin search directory is not the one used by ld's -plugin option. If you want ar to use the linker plugin, you have to copy it 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 it's sufficient to just copy the newest one — literally just the freshest one, that's the whole trick 🫶.
  • --target target — this 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

(no fr the original page just ends the sentence at "See" and leaves you hanging 😭 iykyk)

  • @file — read command-line options from file. The options that get read are inserted right in place of the original @file option. And if file doesn't exist, or can't be read? Then the option gets treated literally, and it is not removed. Rude but fair 🙈.

Options inside file are separated by whitespace. You can sneak a whitespace character into an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) can be included by prefixing the character you want included with a backslash. And the file may itself contain additional @file options — any such options get processed recursively. It's files all the way down, bestie 🌀.

🌸 SEE ALSO 🌸

nm(1), ranlib(1), and the Info entries for binutils. Go read those too, they're part of the lore 📚 ✨.

Copyright (c) 1991-2018 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".

That's the whole page, bestie — binutils-2.30, dated 2018-01-27, filed under AR(1). Now go forth and archive something iconic 🦋👑💜

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