.. should automate the task of deleting the lines in the file ..
Then, in that case, you can specify the filename in your script, then open a filehandle to read from,doing all you wanted done. Like so:

use warnings;
use strict;

my $filename = '...';  # specify the file name here
open my $fh, '<', $filename or die "can't open $filename: $! ";
while ( defined( $_ = <$fh> ) ) {
    print $_ unless $. == 1 or eof;
}
close $fh or die "can't close $filename: $!";
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Thanks for your time. I tried with below code. but it deleted just first line. Can you please help me to delete last 2 lines as well

#!/usr/bin/perl
use strict;
use warnings;

my $file='tgtfile.txt';

open STDOUT, ">", $file or die "$0: open: $!";
open STDERR, ">&STDOUT"        or die "$0: dup: $!";

my $filename = 'srcfile_20140319.txt';  # specify the file name here
open my $fh, '<', $filename or die "can't open $filename: $! ";
while ( defined( $_ = <$fh> ) ) {
    print $_ unless $. == 1 or eof;
}
close $fh or die "can't close $filename: $!";
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