Since the OP states that he/she is a beginner with perl, some explanation of
Zaxos regex might be useful.
From the left:
- /^[A-Z] - the / starts the expression, the ^ means 'at the beginning of the string', the square brackets mean 'any of these characters', and the A-Z means 'the range from A to Z'
- [^_]* - match a number of characters that are not underscores. In this context the ^ character means NOT, rather than its other meaning as 'beginning of line'
- \.html$/ - the \ escapes the dot, which would otherwise (in a regex) mean 'any character', html is obvious, then the regex closes with $, meaning 'end of string', and finally the / ends the expression.
The rest of the regex is either plain characters, or variations on these, so thats probably sufficient.