$x =~ tr/://d;
my $y = pack('H*', $x);

##</code><code>##

my $y = pack('H*', $x =~ tr/://dr);  # 5.14+ required

##</code><code>##

(my $y = $x) =~ s/([0-9a-fA-F]{2}):?/chr(hex($1))/eg;

##</code><code>##

my $y = $x =~ s/([0-9a-fA-F]{2}):?/chr(hex($1))/egr;  # 5.14+ required

##</code><code>##

my $y = pack 'C*', map hex, split /:/, $x;

##</code><code>##

my $y = join '', map chr hex, split /:/, $x;