As for the greps externally - I recall finding this in a perl tutorial many moons ago, and never learned it another way. Might you have a link that explains it internally?

You'd find that described under "regular expressions". As an example,

  open(PROCS, "ps -a | grep $process |");
  while ( my $proc = <PROCS> ) {
      # ...
  }
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can be rewriten (assuming $process holds an alphanumeric string) as

  open(PROCS, "ps -a |");
  while ( my $proc = <PROCS> ) {
      next if $proc !~ /$process/;
      # ...
  }
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Regular expressions are your friends. Learning about them pays off in many ways.