In addition to the fine advice given so far, I'd like to add some other WTDI:

  #!/bin/perl -ni.bak
  print $. < 3 ? () : $. > 3 ? $_ : "new third\n";
[download]

  #!/bin/perl -ni.bak
    print
  } BEGIN {
    scalar <>; scalar <>; scalar <>;
    print "This text replaces the third line.\n";
  } {
[download]

Of course, it doesn't work right if you specify more than one file on the command line, but hey...

jdporter
The 6th Rule of Perl Club is -- There is no Rule #6.