NAME
ar - create, modify, and extract from archives
SYNOPSIS
ar [
-X32_64] [­]p[mod [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 member­name 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 --print­armap 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 is designed to be compatible with two different facilities. You can control its activity
using command­line options, like the different varieties of
ar on Unix systems; or, if you
specify the single command­line 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 command­line argument.
If you wish, you may begin the first command­line 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.
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.
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 object­file 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.
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.
SEE ALSO
nm
(1), ranlib (1), and the Info entries for binutils.
COPYRIGHT
Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001 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 1.1 or any later version published by the Free
Software Foundation; with no Invariant Sections, with no Front­Cover Texts, and with no
Back­Cover Texts. A copy of the license is included in the section entitled ``
GNU Free
Documentation License''.