AR(1) GNU Development Tools AR(1)NAMEar - create, modify, and extract from archives
SYNOPSISar [-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
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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.
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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).
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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
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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 ALSOnm(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, 2005 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''.
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