How about the following:

use Modern::Perl;

print for grep /\S/, <DATA>;

__DATA__
This is not a blank line.

This is not a blank line.

This is not a blank line.

This is not a blank line.
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Output:

This is not a blank line.
This is not a blank line.
This is not a blank line.
This is not a blank line.
[download]