user-tools/lines

   1 #!/usr/bin/env perl
   2
   3 =pod
   4
   5 =head1 NAME
   6
   7 lines - Output only the given lines of the input stream
   8
   9 =cut
  10
  11
  12
  13 if(grep {$_ eq '--help'} @ARGV)
  14 {
  15         die "Usage: $0 [<RANGES> [<RANGES> [...]]] [-- <FILE> [<FILE> [...]]]
  16   Read from from FILEs if specified, STDIN otherwise.
  17   RANGES is comma-delimited list of line numbers and inclusive ranges.
  18   Special symbol 'EOF' represents the end of the input file.
  19   Examples:
  20     1
  21     2-10
  22     1,5-10
  23     2,4,6,8,10-EOF\n";
  24 }
  25
  26 my @ranges;
  27
  28 while(exists $ARGV[0])
  29 {
  30         if($ARGV[0] eq '--')
  31         {
  32                 shift @ARGV;
  33                 last;
  34         }
  35         for my $range (split /,/, $ARGV[0])
  36         {
  37                 if($range =~ /^(\d+)(?:-(\d+|EOF))?$/)
  38                 {
  39                         push @ranges, [$1, $2];
  40                 }
  41                 else
  42                 {
  43                         die "invalid range: $range\n";
  44                 }
  45         }
  46         shift @ARGV;
  47 }
  48
  49 # load this delayed
  50 eval 'use ARGV::readonly; 1' or die;
  51
  52 while(<>)
  53 {
  54         $. = 1 if $ARGV ne $prev_ARGV;
  55         my $include = 0;
  56         for my $range (@ranges)
  57         {
  58                 my ($from, $to) = @$range;
  59                 if(defined $to)
  60                 {
  61                         if($. >= $from and ($to eq 'EOF' or $. <= $to)) { $include = 1; }
  62                 }
  63                 else
  64                 {
  65                         if($. == $from) { $include = 1; }
  66                 }
  67         }
  68         if($include)
  69         {
  70                 print;
  71         }
  72         $prev_ARGV = $ARGV;
  73 }