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


while (defined (my $line =<DATA>) and $line !~ /^\s*$/)
{
    print "do somehing with non blank line\n";
}  

__END__
Global symbol "$line" requires explicit package name (did you forget to declare "my $line"?) at C:\Users\mmtho\Documents\PerlProjects\Monks\test_myVar_inwhile_ver2.pl line 6.
Execution of C:\Users\mmtho\Documents\PerlProjects\Monks\test_myVar_inwhile_ver2.pl aborted due to compilation errors.