#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?i)^(?=(?:\/[a-z0-9s_@\-/.]{1,255})+).{1,4095}$"
Local $sString = "/whatever/thisisnotapornstash/StillNot255CharactersButTheNextFolderIs/BPLrmwQRjmtwIGEMDcgGk1BCRY6ZkKzsHoWqJNzGxCzlGTSZkfOei0QD2S3bGfqSMJMPxuvgHhUJotNgh3hGDYD01n56JiZy32JygaHHDLQbGWtkbFJy5BrMP5s6eL6V8Kcft71CxHZUMEEJ2LbYExYtPxaWuQ9USUCxbt7wTIjALoLN6aHW0GovD5euXWsYuOsqvyGuzJqjaohM9FFNmMz7ul0R4HxzTWWQqCZ8hp6O2yipRTs5k4RmGCTLfdsadsanY/ "
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYFULLMATCH)
; Present the entire match result
_ArrayDisplay($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