ar - create, modify, and extract from archives
ar [
--plugin name] [
-X32_64] [
-]
p[
mod
[
relpos] [
count]]
archive [
member...]
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.
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
archives. Such an archive is useful for building libraries for use within a
local build, where the relocatable objects are expected to remain available,
and copying the contents of each object would only waste time and space. Thin
archives are also
flattened, so that adding one or more archives to a
thin archive will add the elements of the nested archive individually. 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.
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, the archive's symbol table index
is not updated, even if it already existed; you can use ar s or
ranlib explicitly to update the symbol table index.
However, too many different systems assume quick append rebuilds the index,
so GNU ar implements q as a synonym for r.
- 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.
- 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.
Files cannot be extracted from a thin archive.
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.
- 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.
- 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
- 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.
- 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.
ar ignores an initial option spelt
-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.
The optional command line switch
--plugin name causes
ar to
load the plugin called
name which adds support for more file formats.
This option is only available if the toolchain has been built with plugin
support 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.
nm(1),
ranlib(1), and the Info entries for
binutils.
Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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".