5
If you're just trying to strip the first character regardless of what it is then SubStr(Contents, 2)
would be a much better. I know you said you weren't married to regex, but if you wanted to do the same with regex you would do 's)^.'
, per the documentation the "s" option makes the "." character include newlines and it's related characters. By default for some reason Autohotkey's regexes exclude newlines from the ".".