[97603] in RedHat Linux List
Re: grep syntax
daemon@ATHENA.MIT.EDU (William Stearns)
Wed Nov 4 00:08:18 1998
Date: Wed, 4 Nov 1998 00:11:11 -0500 (EST)
From: William Stearns <wstearns@pobox.com>
To: "Canary, Robert W. -- Robert W. Canary" <rwcanary@ohiocounty.net>,
rwcanary@mail.lig.bellsouth.net
cc: ML-redhat <redhat-list@redhat.com>
In-Reply-To: <363FDCCB.265E@ohiocounty.net>
Resent-From: redhat-list@redhat.com
Reply-To: redhat-list@redhat.com
Good evening, Robert,
On Tue, 3 Nov 1998, Robert W. Canary wrote:
> I am trying find the correct syntax for grep a directory and excluding
> certain files from the output.
>
> EXCEPTIONS="ttyC4 ttyC5"
>
> command ls /var/lock | grep tty[SC] | {filter out $EXCEPTIONS}
>
> I can filter out the exception with "grep -v ttyC4 | grep -v ttyC0", but
> I need to be able to feed it a variable that contians a list of some
> sort.
How about:
EXCEPTIONS="ttyC4|ttyC5"
ls /var/lock | grep tty[SC] | egrep -v "(${EXCEPTIONS})"
The egrep (xxx|yyy|zzz) syntax tells grep to match anything with
xxx OR yyy OR zzz in it. The -v says to discard anything with xxx or yyy
or zzz in it. You do have to use the vertical pipe sysmbol as the
separator in your list. If this is a problem, try:
EXCEPTIONS="ttyC4 ttyC5" #Set by a previous part of your script, perhaps
EXCEPTIONS=`echo ${EXCEPTIONS} | sed -e 's/ /|/'`
ls /var/lock | grep tty[SC] | egrep -v "(${EXCEPTIONS})"
Cheers,
- Bill
---------------------------------------------------------------------------
Unix _is_ user friendly. It's just very selective about who its friends
are. And sometimes even best friends have fights.
William Stearns (wstearns@pobox.com)
Mason, buildkernel, and named2hosts are at: http://www.pobox.com/~wstearns
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