#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(((\r?\n|\s)*[A-Za-z0-9+\/]){4})*(((\r?\n|\s)*[A-Za-z0-9+\/]){2}((\r?\n|\s)*=){2}|((\r?\n|\s)*[A-Za-z0-9+\/]){3}((\r?\n|\s)*=){1})?"
Local $sString = "abdcdd fijfokkkmAS/+=" & @CRLF & _
"" & @CRLF & _
"assdoifjfjidodijfjjjDDD"
Local $sSubst = "<<<$0>>>"
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