GNU bug report logs - #5812
expr: Difference in behavior of match and :

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Bob Proulx <bob <at> proulx.com>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#5812: marked as done (expr: Difference in behavior of match
 and :)
Date: Mon, 05 Apr 2010 04:43:02 +0000

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Your message dated Sun, 4 Apr 2010 22:42:13 -0600
with message-id <20100405044212.GA22010 <at> dementia.proulx.com>
and subject line Re: bug#5812: expr: Difference in behavior of match and :
has caused the GNU bug report #5812,
regarding expr: Difference in behavior of match and :
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
bug report if necessary, and/or fix the problem forthwith.

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5812: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=5812
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From: Adil Mujeeb <mujeeb.adil <at> gmail.com>
To: bug-coreutils <at> gnu.org
Subject: expr: Difference in behavior of match and :
Date: Wed, 31 Mar 2010 18:35:16 +0530

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Hello team,

I have tried following snippet in a bash script:

-bash-3.1$userid=`expr "uid=11008(ADILM) gid=1200(cvs),1400(build)" :
".*uid=[0-9]*(\(.[0-9a-z]*\)) .*"`
-bash-3.1$echo $userid
ADILM
-bash-3.1$

To my knowledge it should not able to extract ADILM as the regex does not
include uppercase letters (A-Z).

In the expr man page it is mentioned that:

-----8<----------
match STRING REGEXP
 same as STRING : REGEXP
-----8<----------

So i tried following snippet:-

-bash-3.1$ userid=`expr match "uid=11008(ADILM) gid=1200(cvs),1400(build)"
".*uid=[0-9]*(\(.[0-9a-z]*\)) .*"`
-bash-3.1$ echo $userid

-bash-3.1$

I changed the regex and added uppercase letters:-
-bash-3.1$ userid=`expr match "uid=11008(ADILM) gid=1200(cvs),1400(build)"
".*uid=[0-9]*(\(.[0-9A-Za-z]*\)) .*"`
-bash-3.1$ echo $userid
ADILM
-bash-3.1$

So it means that match is not same as ":". As per observation ":" uses
case-insensitive matching while match is strict case sensitive matching.

Can you update the man page OR let me know if i am doing anything wrong?

Package:-
-bash-3.1$ rpm -qf /usr/bin/expr
coreutils-5.97-12.1.el5
-bash-3.1$

Thanks and Regards,
Adil Mujeeb

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From: Bob Proulx <bob <at> proulx.com>
To: Adil Mujeeb <mujeeb.adil <at> gmail.com>
Cc: 5812-done <at> debbugs.gnu.org
Subject: Re: bug#5812: expr: Difference in behavior of match and :
Date: Sun, 4 Apr 2010 22:42:13 -0600

Adil Mujeeb wrote:
> Thanks Bob for such a nice explanation and your instinct is right. It is
> locale problem.
> ...
> And the other point you made is also right. I didn’t realize that I was
> using another session for comparing the result with match which ahs
> different locale:-

I thought it might have been something like that.

> I never knew that locale has effect on the behavior. We can close this bug.

I will close the bug with this message then.

> Thank you so much for your time and details, I have learnt new thing :)

I am glad to have helped!

> Also, thanks for correcting my regex.

Sure thing!

Bob

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