and

   1 #!/usr/bin/perl
   2
   3 =head1 NAME
   4
   5 and - print lines that are present in one file and another
   6
   7 =head1 SYNOPSIS
   8
   9 and file
  10
  11 and [file|-] [file|-] ...
  12
  13 =head1 DESCRIPTION
  14
  15 B<and> reads the specified files and prints out the lines that are common
  16 to all files, in the order they are listed in the last file. Use "-" to
  17 make it read a file from standard input. If only one file is specified,
  18 B<and> first reads standard input, and compares it with the specified file.
  19
  20 =head1 AUTHOR
  21
  22 Copyright 2006 by Joey Hess <joey@kitenet.net>
  23
  24 Licensed under the GNU GPL.
  25
  26 =cut
  27
  28 use warnings;
  29 use strict;
  30
  31 if (@ARGV == 0) {
  32         die "usage: and [file|-] [file|-] ...\n";
  33 }
  34
  35 if (@ARGV == 1) {
  36         unshift @ARGV, "-";
  37 }
  38
  39 my %seen;
  40 foreach my $fn (@ARGV) {
  41         open (IN, $fn) || die "and: read $fn: $!\n";
  42         while (<IN>) {
  43                 chomp;
  44                 $seen{$_}++;
  45                 if ($seen{$_} == @ARGV) {
  46                         print "$_\n";
  47                 }
  48         }
  49         close IN;
  50 }