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