ar - create, modify, and extract from archives
SYNOPSIS
ar [-X32_64] [-]p[mod [relpos] [count]] archive [mem
ber...]
DESCRIPTION
The GNU `ar' program creates, modifies, and extracts from
archives. An archive is a single file holding a collec
tion 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), times
tamp, 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 com
monly needed subroutines.
`ar' creates an index to the symbols defined in relocat
able 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 rou
tines 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' 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 modi
fier flags mod in any order, within 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 dif
ference 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 opera
tion; 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 replace
ment). This operation differs from q in that any
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 pre
sent in the archive. Normally only the member name is
shown; if you also want to see the modes (permis
sions), 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 behav
ior:
`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).
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 com
plaint), but other archive creators can. This option
will cause GNU `ar' to match file names using a com
plete path name, which can be convenient when extract
ing 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.
archive. If you would like to insert only those of
the files you list that are newer than existing mem
bers of the same names, use this modifier. The u mod
ifier 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 oper
ation. Many operations display additional informa
tion, 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 com
patibility 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 Documenta
tion License, Version 1.1 or any later version published
by the Free Software Foundation; with no Invariant Sec
tions, 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".
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