I have a regex for session ID extraction:[root@docker tmp]# grep -oE \[[0-9].+\] logfile[113a6d9e-7b06-42c6-a52b-7a4e4d2e216c][113a6d9e-7b06-42c6-a52b-7a4e4d2e216c][root@docker tmp]#How can I hide the square brackets from the output?
Hide part of match from grep output
grep;regular expression
Instead of using extended-regex grep (-E), use perl-regex grep instead (-P), with a lookbehind and lookahead.$ grep -oP (?<=\[)[0-9].+(?=\]) logfile113a6d9e-7b06-42c6-a52b-7a4e4d2e216c113a6d9e-7b06-42c6-a52b-7a4e4d2e216cHere, (?<=\[) indicates that there should be a preceding \[, and (?=\]) indicates that there should be a following \], but not to include them in the match output.