Select Code to Download

foreach $key (keys %hash) {
    $key = quotemeta $key;
    $text =~ s/$key/$hash{$key}/eg;
}

use Benchmark;

...
Benchmark: timing 100000 iterations of Alternation, Simple loop...
Alternation:  5 wallclock secs ( 4.12 usr +  0.00 sys =  4.12 CPU) @ 2
+4271.84/s (n=100000)
Simple loop: 10 wallclock secs ( 9.72 usr +  0.00 sys =  9.72 CPU) @ 1
+0288.07/s (n=100000)