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Perl Language Reference Manual
by Larry Wall and others
Paperback (6"x9"), 724 pages
ISBN 9781906966027
RRP £29.95 ($39.95)

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-p

causes Perl to assume the following loop around your program, which makes it iterate over filename arguments somewhat like sed:

LINE:
  while (<>) {
      ...             # your program goes here
  } continue {
      print or die "-p destination: $!\n";
  }

If a file named by an argument cannot be opened for some reason, Perl warns you about it, and moves on to the next file. Note that the lines are printed automatically. An error occurring during printing is treated as fatal. To suppress printing use the -n switch. A -p overrides a -n switch.

BEGIN and END blocks may be used to capture control before or after the implicit loop, just as in awk.

ISBN 9781906966027Perl Language Reference ManualSee the print edition