#!/usr/bin/perl

use strict;
use warnings 'all';
use File::stat;      # use the object-oriented interface to stat

my $file = "rajesh.txt";
my $file_timestamp = stat($file)->mtime;   # gets the file-modified time, in 
                                           # seconds since the epoch
                                           
#  my $startTime = time();                 # You don't even really need this -- Perl has a
                                           # built-in variable, $^T, that records when your
                                           # script started to run. See the perlvar manpage.

my $timestamp = localtime($^T);            # localtime, with no argument, assumes
                                           # localtime(time). My example gets the localtime of $^T.
                                           # Assigning this to a scalar variable, as
                                           # you do here, gives you the
                                           # formatted ctime. You also could
                                           # have done localtime(time) here,
                                           # or just localtime with no argument.

my $rajesh = $^T - $file_timestamp;        # This is really all you need to do here. You could
                                           # also use the time function to get the current time,
                                           # i.e. $rajesh = time - $file_timestamp

my $pretty_file_timestamp = localtime($file_timestamp);  # Get the scalar (ctime) format

print "The current time is = $timestamp\n";
print "The file modified time is = $pretty_file_timestamp\n";
print "The difference between file modified time and current time is = $rajesh\n";