index|substr

 #!/usr/bin/perl

 use strict;
 use warnings;

 $_ = 'duwanxkm,c.,df;oq123@#!@%$#^';
 my $d ='d';my $o = 'o';my $where =index($_,$o);print "$where\n";
 $where =index($_,$d,);print "$where\n";
 $where =index($_,'y');print "$where\n";
 my $lastword = rindex("%23%4546","%",);print "$lastword\n";

 #15
 #12
 #-1
 #3
 #0

 my $sentence = 'very very long';
 my $cut = substr ($sentence,index($sentence,'long'),);substr ($sentence,index($sentence,'long'),)='yoo!';print "$sentence\n$cut\n";
 substr ($sentence,-) =~ s/o/AAAAAA/g;print "$sentence\n";

 #very very yoo!g
 #lon
 #very very yAAAAAAAAAAAA!g

 my $new = substr ($sentence,,,"GOOOOO");print "$new\n$sentence\n";

 #y very yAA
 #verGOOOOOAAAAAAAAAA!g