use strict;
use warnings;

my $username;
my $color;

while(<>){
    chomp;
    s/"//g;
    ($username,$color) = (split /,/,$_)[2,3];
    print STDOUT "test of username: $username\n";#NEW
    print STDOUT "test of dollar-underscore: $_\n";#NEW ALSO
    if ("agag" =~ m/($username)/){
	print STDOUT "here is the username: $username\n";
	print STDOUT "here is dollar-underscore: $_\n";
    }
}

##</code><code>##

test of username: adad
test of dollar-underscore: ADELMAN,John,adad,Ray
test of username: agag
test of dollar-underscore: AGAN,John,agag,Aditya
test of username: ahah
test of dollar-underscore: AHMED,John,ahah,Conor
Use of uninitialized value $username in concatenation (.) or string at test.pl line 11, <> line 4.
test of username: 
test of dollar-underscore: 
Use of uninitialized value $username in regexp compilation at test.pl line 13, <> line 4.
Use of uninitialized value $username in concatenation (.) or string at test.pl line 14, <> line 4.
here is the username: 
here is dollar-underscore: