>>>cat temp.txt
my dog is (red1)
my cat is (blue1)
my dog is (red2)
my cat is (blue2)
my dog is (red3)
my cat is (blue3)
my dog is (red4)
my cat is (blue4)
my dog is (red5)
my cat is (blue5)
my dog is (red6)
my cat is (blue6)

##</code><code>##

#!/usr/bin/perl

$mystring = join("", <>);
#print $&;
print "-----------mystring--------------------------\n";
print $mystring;
print "------------variables----------------------------\n";
if ($mystring =~ m/my.*?\((\S*?)\)/g) {
#if ($mystring =~ s/my.*?\((\S*?)\)/xxxxxxx/g) {
print "$1 \n";
print "-----------mystring again--------------------------\n";
print $mystring;
print "-----------------------------------------\n";
}

##</code><code>##

>>>>cat temp.txt | perl temp.pl
-----------mystring--------------------------
my dog is (red1)
my cat is (blue1)
my dog is (red2)
my cat is (blue2)
my dog is (red3)
my cat is (blue3)
my dog is (red4)
my cat is (blue4)
my dog is (red5)
my cat is (blue5)
my dog is (red6)
my cat is (blue6)
------------variables----------------------------
red1
-----------mystring again--------------------------
my dog is (red1)
my cat is (blue1)
my dog is (red2)
my cat is (blue2)
my dog is (red3)
my cat is (blue3)
my dog is (red4)
my cat is (blue4)
my dog is (red5)
my cat is (blue5)
my dog is (red6)
my cat is (blue6)
-----------------------------------------