#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "\*([^*]+)\*"
Local $sString = "What kind of *vegetable* is it?" & @CRLF & _
                "I hope I am not late." & @CRLF & _
                "All *the good* shows are *no longer* broadcasting." & @CRLF & _
                "This line contains entries with numbers (*1+2=3*) and punctuation too (*this is a sentence.*)"
Local $sSubst = "<b>$1</b>"
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