Using file descriptor 4 in bash scripts

May I safely use file descriptor 4 in a bash script?

Unruh

2006-10-17 15:24:05 UTC

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

For what?

Bill Marcum

2006-10-17 15:19:19 UTC

["Followup-To:" header set to comp.os.linux.misc.]
On Tue, 17 Oct 2006 16:27:00 +0300, Angel Tsankov

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

As far as I know, yes. How do you want to use it?

--
Bower's Law:
Talent goes where the action is.

Chris F.A. Johnson

2006-10-17 19:22:37 UTC

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

Yes; the three descriptors in normal use are 0 (stdin), 1 (stdout),
and 2 (stderr).

--
Chris F.A. Johnson, author | <http://cfaj.freeshell.org>
Shell Scripting Recipes: | My code in this post, if any,
A Problem-Solution Approach | is released under the
2005, Apress | GNU General Public Licence

Angel Tsankov

2006-10-17 20:48:33 UTC

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

Yes; the three descriptors in normal use are 0 (stdin), 1
(stdout),
and 2 (stderr).

Does this mean that fd 4 (or fd 3) won't be used by bash and is
available to bash scripts?

Chris F.A. Johnson

2006-10-17 21:15:22 UTC

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

Yes; the three descriptors in normal use are 0 (stdin), 1
(stdout),
and 2 (stderr).

Does this mean that fd 4 (or fd 3) won't be used by bash and is
available to bash scripts?

That is correct.

Angel Tsankov

2006-10-17 21:34:31 UTC

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

Yes; the three descriptors in normal use are 0 (stdin), 1
(stdout),
and 2 (stderr).

Does this mean that fd 4 (or fd 3) won't be used by bash and
is
available to bash scripts?

That is correct.

This is fine. Is it documented anywhere?

Chris F.A. Johnson

2006-10-17 22:28:44 UTC

Post by Angel Tsankov
May I safely use file descriptor 4 in a bash script?

Yes; the three descriptors in normal use are 0 (stdin), 1
(stdout),
and 2 (stderr).

Does this mean that fd 4 (or fd 3) won't be used by bash and
is
available to bash scripts?

That is correct.

This is fine. Is it documented anywhere?

You can use any descriptor, even 0, 1, and 2. See the bash man page
for more information. See also the POSIX spec:
<http://www.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_07>.

Bill Marcum

2006-10-23 18:46:48 UTC

["Followup-To:" header set to comp.os.linux.misc.]
On Wed, 18 Oct 2006 00:34:31 +0300, Angel Tsankov