#!/usr/bin/perl --
use strict; use warnings;
use Data::Dump qw/ dd /;

my $input = 'servername.EXAMPLE.com  servername';
my $wantedOutput = 'newname.EXAMPLE.com  newname';
my $replacement = 'newname';
my $uname = quotemeta 'servername'; ###

dd $input;

for( $input ){
    s/$uname/$replacement/gi;
}

dd $input;
dd $wantedOutput ;
__END__
"servername.EXAMPLE.com  servername"
"newname.EXAMPLE.com  newname"
"newname.EXAMPLE.com  newname"