give perlwhich a module name, and it will tell which which file defines it.

perlwhich.pl

#!/usr/bin/perl

use strict;

my $syntax = <<EOF;
syntax: perlwhich [-v] <package>
displays the file where <package> is implemented
-v shows the version of any packages found
EOF

my $show_version = grep { $_ eq '-v' } @ARGV;
@ARGV = grep { !/^-/ } @ARGV;

my $package = shift or die $syntax;
$package =~ s/-/::/g;
my $file = $package;
$file =~ s/::/\//g;
$file .= '.pm';

our @INC;
foreach my $dir (@INC) {
    next unless -e "$dir/$file";
    print "$dir/$file";
    if ($show_version) {
        require "$dir/$file";
        my $version;
        eval '$version = $' . $package . '::VERSION';
        print " v$version" if $version;
    }
    print "\n";
    exit;
}
print "$package not found\n";