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
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 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, 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 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.
- 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, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
2002, 2003, 2004 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
Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is
included in the section entitled ``GNU Free Documentation License''.