From: Christopher L. Barnard (cbar44@tsg.cbot.com)
Date: Mon Jan 31 2005 - 14:04:10 EST
I asked:
> I have a quick regexp question.
>
> I want to match, case does not matter, a string
> foo: bar
> where foo starts the line, there can be one or more whitespace characters
> between the : and the bar, and there can be zero or more whitespace
> characters between the bar and the end of line. "whitespace characters"
> here means spaces or tabs.
>
> /usr/bin/egrep -i ^foo:[ ][ ]*bar[ ]*$
>
> works with any combination of spaces I use. But when I add \t to the regex:
>
> /usr/bin/egrep -i ^foo:[ \t][ \t]*bar[ \t]*&
>
> it fails. I have tried escaping the \t (as in, \\t), but that did not help.
> I tried bracketing with ( and ), but that did not help. I have used double
> and single quotes, and that did not help. Can anyone suggest how to write an
> RE that will see a tab character? TIA and I will summarize.
The answer:
The "\t" is how it is written down in documentation. But to use the tab
character in a regex, hit the tab key. literally. It works like a charm.
For the individuals who suggested /:space:/ : yes, that would work in a more
powerful shell. I want this to work in the basic /bin/sh, and understanding
of /:space:/ in egrep is something added in ksh.
For the individuals who did not understand why I would have the [ =t]*$ at
the end: that will capture whitespace between what looks like the last
character of the string and the end-of-line. Whitespace at the end doesn't
harm anything, so there is no reason to check for it.
I also got a few links to get the hex code for a tab. Thanks. (TAB= \011).
Thanks to:
Doc G <maddocg@verizon.net>
Alex Stade <alex@trdlnk.com>
Larry Anta <lanta@ryerson.ca>
Kurt Schulte <r2kurts@yahoo.com>
Darren Dunham <ddunham@taos.com>
Karyn Williams <karyn@calarts.edu>
Colin Bigam <colin@west.gecems.com>
Crist Clark <crist.clark@globalstar.com>
John Leadeham <jl@lammtarra.fslife.co.uk>
David Markowitz <DMarkowitz@litronic.com>
Hans Jacobsen <HJacobsen@grandcentral.com>
R A Lichtensteiger <sunmanagers@throwawaydomain.com>
+-----------------------------------------------------------------------+
| Christopher L. Barnard O When I was a boy I was told that |
| cbarnard@tsg.cbot.com / \ anybody could become president. |
| (312) 347-4901 O---O Now I'm beginning to believe it. |
| http://www.cs.uchicago.edu/~cbarnard --Clarence Darrow |
+----------PGP public key available via finger or PGP keyserver---------+
_______________________________________________
sunmanagers mailing list
sunmanagers@sunmanagers.org
http://www.sunmanagers.org/mailman/listinfo/sunmanagers
This archive was generated by hypermail 2.1.7 : Wed Apr 09 2008 - 23:30:05 EDT