s/// doesn't work like that. In s/PATTERN/REPLACEMENT/ the PATTERN in a regular expression, like the one you've given, but the REPLACEMENT part isn't. The replacement is just a string use like a regular double-quoted string. The /e makes the string evaluate, i.e. act like code instead of a piece of chars and [A-Z]* isn't valid Perl code. So remove the e, don't use a pattern in the replacement part, and ultimately fix your pattern. That might include capturing a part of the match matched by PATTERN, and you then interpolate that match in the replacement part (as the replacement is just a double-quoted string). What you really want to have, I think, is 

$file =~ s/^([A-Z].*)\.pdf\z/$1/;

[download]
Now this introduce quite a few things, like ^, (), .*, \., \z, and $1. You can read more about them in perlretut and other documents that come with Perl. To learn about s/// see perlop.

Update: Didn't read closely enough; adjusted the pattern to fit the OP.

ihb

See perltoc if you don't know which perldoc to read!

In reply to Re: using s/// to remove file extensions by ihb
in thread using s/// to remove file extensions by Plotinus

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