http://ssl.webangel.ie/ 2026-05-28T11:43:17+00:00 http://ssl.webangel.ie/ http://ssl.webangel.ie/lib/exe/fetch.php?media=wiki:dokuwiki.svg text/html 2025-10-07T09:43:40+00:00 Anonymous (anonymous@undisclosed.example.com) http://ssl.webangel.ie/doku.php?id=linux:classnotes:rh134:bash:regex&rev=1759830220&do=diff Regular Expressions They are a pattern matching tool THey are used by tools like grep awk sed etc You can question the output to see if pattern was found using $? grep stands for global regular expression print it will highlight the pattern if its found