stabu:

They're not just matches ... they're translations. It's not unlikely for several of them to modify the string.

my $s = "   the quick red fox jumped over the lazy brown dog   ";
$s =~ s/^\s+//;
$s =~ s/\s+$//;
$s =~ s/(brown|red)/color/g;
print "<$s>\n";
[download]

should give you:

<the quick color fox jumped over the lazy color dog>
[download]

...roboticus