#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?im)^([0-9A-Fa-f]{8}[-]?[0-9A-Fa-f]{4}[-]?[0-9A-Fa-f]{4}[-]?[0-9A-Fa-f]{4}[-]?[0-9A-Fa-f]{12})$"
Local $sString = "f27a5b7f-0b7c-4e79-aff5-bdb0d34f3a9f" & @CRLF & _
"f27a5b7f0b7c4e79aff5bdb0d34f3a9f"
Local $sSubst = "$1"
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