parrot link substitution

subst2.pl

use strict;
use warnings;
use autodie;
use 5.010;

open my $f, '<', '../issue-map';
my %map;
while (<$f>) {
    chomp;
    my @a = split;
    s/\D+//g for @a;
    $map{$a[1]} = $a[0];
}
BEGIN {$^I = ''}

my $keys = join '|', keys %map;

while (<>) {
    s[https?://trac\.parrot\.org/parrot/ticket/($keys)\b][https://github.com/parrot/parrot/issues/$map{$1}]g;
    print;
}