man > ar(1)

TLDR: ar (tldr-pages)

Create, modify, and extract from Unix archives. Typically used for static libraries (`.a`) and Debian packages (`.deb`).

  • Extract all members from an archive
    ar x {{path/to/file.a}}
  • List contents in a specific archive
    ar t {{path/to/file.ar}}
  • replace or add specific files to an archive
    ar r {{path/to/file.deb}} {{path/to/debian-binary path/to/control.tar.gz path/to/data.tar.xz ...}}
  • Insert an object file index (equivalent to using `ranlib`)
    ar s {{path/to/file.a}}
  • Create an archive with specific files and an accompanying object file index
    ar rs {{path/to/file.a}} {{path/to/file1.o path/to/file2.o ...}}
AR(1)                                   GNU Development Tools                                  AR(1)

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...]

DESCRIPTION
       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
       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.

           Note - if an archive has been created in a deterministic manner, eg 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.  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
       nm(1), ranlib(1), and the Info entries for binutils.

COPYRIGHT
       Copyright (c) 1991-2024 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".

binutils-2.42                                2026-02-09                                        AR(1)
ar(1)
NAME SYNOPSIS DESCRIPTION OPTIONS
--help --version -X32_64 --thin
SEE ALSO COPYRIGHT

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