AR(1) GNU Development Tools AR(1)

NAME
ar--create, modify, and extract from archives.

SYNOPSIS
ar [-]{dmpqrtx}[abcilosuvV] [membername] archive files...

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
may be reconstituted 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 charac-
ters (typical of formats related to a.out) or 16 charac-
ters (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 will create 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 in-
dex table. If an archive lacks the table, another form of
ar called ranlib can be used to add just the table.

ar insists on at least two arguments to execute: one
keyletter specifying the operation (optionally accompanied
by other keyletters specifying modifiers), and the archive
name to act on.

Most operations can also accept further files arguments,
specifying particular files to operate on.

OPTIONS
GNU ar allows you to mix the operation code p and modifier
flags mod in any order, within the first command-line ar-
gument.

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 files; the archive is
untouched if you specify no files to delete.

If you specify the ‘v’ modifier, ar will list 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 li-
brary, if a symbol is defined in more than one mem-
ber.

If no modifiers are used with m, any members you
name in the files arguments are moved to the end of
the archive; you can use the ‘a’, ‘b’, or ‘i’ modi-
fiers 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 spec-
ified, show the member name before copying its con-
tents to standard output.

If you specify no files, all the files in the
archive are printed.

q Quick append; add files 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.

r Insert files 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 files doesn’t exist,
ar displays an error message, and leaves undis-
turbed 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 files that are present
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 any files, 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’ will list 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 files) 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 any files, 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 mem-
bername 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 mem-
bername argument, before the archive specification.
(same as ‘i’).

c Create the archive. The specified archive is al-
ways created if it didn’t 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.

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 mem-
bername argument, before the archive specification.
(same as ‘b’).

l This modifier is accepted but not used.

o Preserve the original dates of members when ex-
tracting them. If you do not specify this modifi-
er, files extracted from the archive will be
stamped with the time of extraction.

s Write an object-file index into the archive, or up-
date 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.

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 in-
formation, such as filenames processed, when the
modifier ‘v’ is appended.

V This modifier shows the version number of ar.

SEE ALSO
‘binutils’ entry in info; The GNU Binary Utilities, Roland
H. Pesch (October 1991). nm(1), ranlib(1).

Permission is granted to make and distribute verbatim
copies of this manual provided the copyright notice and
this permission notice are preserved on all copies.

Permission is granted to copy and distribute modified ver-
sions of this manual under the conditions for verbatim
copying, provided that the entire resulting derived work
is distributed under the terms of a permission notice
identical to this one.

Permission is granted to copy and distribute translations
of this manual into another language, under the above con-
ditions for modified versions, except that this permission
notice may be included in translations approved by the
Free Software Foundation instead of in the original En-
glish.

cygnus support 5 November 1991 4