my $s='aAaAaAaAaAaAAAAaaa';
substr( $s, 1+index( $s, 'A' ) ) =~ s[A][a]g;
print $s;
aAaaaaaaaaaaaaaaaa
Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon