my @array;
while ( my $line = <DATA> ) {
    chomp;
    push @array, $line;
}

for( my $idx = 0; $idx <= $#array; $idx++ ) {
    my $line_no = $idx + 1;
    print "Line $line_no = $array[$idx]\n";
}
__DATA__
Here's the first line
Here's the second line
Here is the third line
Here is the forth line