#!/usr/bin/perl
$_ = "he is a great scienceist!";
s/he/they/;
print $_;
print "\n";
my $string = "big exists!";
$string =~ s/big/replacementbig/g;
print "string: $string\n";
$tt="fff ddd ddfdgfgfdh gff fff dfdshffh";
$tt=~ s/fff/aaa/g;
print "\n $tt";