This sounds to me like a very, very strange UI request. Normally a blank input from the user should be a no op or a re-prompt. But I think this will do what you you have asked for although I'm not sure that this is what you need: 
while ( (my $inputLine =<STDIN>) !~ /^\s*$/ )
{
   print $inputLine;
}

print "WOW null line (only spaces or nothing) - I've bailed!\n";

[download]

\s matches: space,\n,\r,\t,\f.

In reply to Re: die on carriage return by Marshall
in thread die on carriage return by muizelaar

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