#!/usr/bin/perl
use warnings;
use strict;
if ( -e 'file.txt' ) {
print( "Do you want to write over file.txt? (yes or no): " );
chomp( my $response = );
rename( 'file.txt', 'file.old' ) or die( "Error renaming : $!" ) if ( $response eq 'no' );
}
open( FILE, ">file.txt" ) or die( "Error opening: $!" );
print( FILE "A copy of file.txt is saved in file.old.\n" );
close( FILE ) or die( "Cannot close: $!" );