#!/usr/bin/env perl
use strict;
use warnings;

my $text = "blah blah [click me](click me) more stuff\nblah [link here](link here) blah blah";
$text =~ s/(\[[^]]+]\()/$1\//g; # make links absolute
$text =~ /(\[[^]]+]\(\/)([^\)]+)/;
my $part1 = $1;
my $part2 = $2;
my $orig_part2 = $part2;
$part2 =~ s/ /-/g;
$text =~ s/\Q$part1$orig_part2\E/$part1$part2/g;