not exactly sure what your

        print line until ( !($line =~ /\s+/ ) )
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means, but here's a pseudocode that I _think_ is close to what you want:

      while( my $ln = <$filehandle> ) {
             next if $ln =~ /^\s*$/;

             if( $ln ....  [ your conditions ] ) { 
                   while( $ln = <$filehandle> ) {
                         last if $line =~ /\s*$/;
                         print $line; # or whatever
                   }
              }
       }
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