Wow. You're using Perl and you're still not aware of one of the traditional selling points of Perl: regular expressions. 
($substring) = $fullstring =~ /^.{2}(.*?)X/s;

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That's everything from behind the second character up till the first "X".

In reply to Re: Substring consisting of all the characters until "character X"? by bart
in thread Substring consisting of all the characters until "character X"? by TheMartianGeek

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