open(FH, "wrongs") or die $!;
open(FH2, ">wrongs2") or die $!;
while ($line = <FH>) {
   $line =~ s/wrongs/wrongs3/;
   print FH2 "$line";
}
close (FH);
close (FH2);

##</code><code>##

perl -lpe 's/wrongs/wrongs3/' wrongs >wrongs2

##</code><code>##

perl -lpi -e 's/wrongs/wrongs3/' wrongs

##</code><code>##

perl -lpe "s/wrongs/wrongs3/" wrongs >wrongs2

##</code><code>##

perl -lpi.bak -e "s/wrongs/wrongs3/" wrongs

##</code><code>##

perl -lpi '$c++ if s/wrongs/wrongs3/; END{warn "count=$c\n"}' wrongs

##</code><code>##

$ time perl -lpe '$c++ if s/sex/cool/; END{warn "count=$c\n"}' gse1.log >/dev/null 
count=2840

real    0m19.062s
user    0m16.736s
sys     0m0.940s

##</code><code>##

perl -lpi '$c+=s/wrongs/wrongs3/g; END{warn "count=$c\n"}' wrongs

##</code><code>##

perl -lpi 's/wrongs($c++)/wrongs3/g; END{warn "count=$c\n"}' wrongs