You can do it with File::Basename, which is in the core distribution for Perl:

use File::Basename;

my $s = "/home/virtual/path/to/www/some/directory/filename.txt";
my $fname = basename($s);
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To get rid of the file extension, use fileparse (from the same module).   You can use the command perldoc File::Basename for more details.

Update:  As helphand points out, you can also supply the extension (or a list of extensions) to strip, to basename.  Of course, you could also just use a regex to strip any extension afterwards, such as:

$fname =~ s/\.[^\.]*$//;
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