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

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

__END__
Value of <HANDLE> construct can be "0"; test with defined() at C:\Users\mmtho\Documents\PerlProjects\Monks\test_myVar_inwhile.pl line 5.
Global symbol "$line" requires explicit package name (did you forget to declare "my $line"?) at C:\Users\mmtho\Documents\PerlProjects\Monks\test_myVar_inwhile.pl line 5.
Execution of C:\Users\mmtho\Documents\PerlProjects\Monks\test_myVar_inwhile.pl aborted due to compilation errors.