#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)^3[Aa-Zz]"
Local $sString = "Oct 8 22:00:00 dev-db crond[18340]: (root) CMD (/bin/sh /home/root/bin/system_check &)" & @CRLF & _
"Oct 8 23:00:00 dev-db crond[20348]: (oracle) CMD (/bin/sh /home/oracle/bin/cleanup.sh &)" & @CRLF & _
"Oct 8 23:59:00 dev-db crond[20399]: (john) CMD (/bin/sh /home/john/bin/backup.sh &)"
Local $sSubst = "\1 -> \3"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm