#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?m)^(\S+|\S+\s+\d+\s+\S+) \S+ postfix\/(submission\/)?smtpd(?:\[\d+\])?: \w+: client=\S+\[(\S+)\], sasl_method=(?:(?i)LOGIN|PLAIN|(?:CRAM|DIGEST)-MD5), sasl_username=(\S+)$"
Local $sString = "Sep 23 11:45:31 el7p17 postfix/smtpd[39220]: CB957400A36E: client=unknown[192.168.1.122], sasl_method=PLAIN, sasl_username=test@example.com"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYGLOBALFULLMATCH)
Local $aFullArray[0]
For $i = 0 To UBound($aArray) -1
_ArrayConcatenate($aFullArray, $aArray[$i])
Next
$aArray = $aFullArray
; Present the entire match result
_ArrayDisplay($aArray, "Result")
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