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 =head1 SYNOPSIS
  10
  11 lines [I<RANGES> [I<RANGES> [...]]] [-- I<FILE> [I<FILE> [...]] | < I<FILE>]
  12
  13 =head1 DESCRIPTION
  14
  15 Read from from I<FILE>s if specified, STDIN otherwise.
  16 I<RANGES> is comma-delimited list of line numbers and inclusive ranges.
  17 Special word "B<EOF>" in a range's upper limit represents the end of the file.
  18
  19 Starts the line numbering from 1.
  20
  21 If multiple files are given, restart the line numbering on each file.
  22
  23 Always displays the lines in the in-file order, not in arguments-order,
  24 how they were given in I<RANGES> arguments; ie. does not buffer or seek in the input files.
  25 So I<lines 1,2> and I<lines 2,1> both display the 1st line before the 2nd.
  26
  27 =head1 EXAMPLES
  28
  29 =over 4
  30
  31 =item lines 1
  32
  33 =item lines 2-10
  34
  35 =item lines 1,5-10 3
  36
  37 =item lines 2-4 6,8 10-EOF
  38
  39 =back
  40
  41 =head1 EXIT STATUS
  42
  43 Exit 2 if there was a range which was not found,
  44 ie. a file had less lines than requested.
  45
  46 =cut
  47
  48 use Data::Dumper;
  49 use Pod::Usage;
  50 use List::MoreUtils qw/all any none/;
  51
  52
  53 if(grep {$_ eq '--help'} @ARGV)
  54 {
  55         pod2usage(-exitval=>0, -verbose=>99);
  56 }
  57
  58 my @ranges;
  59
  60 while(exists $ARGV[0])
  61 {
  62         if($ARGV[0] eq '--')
  63         {
  64                 shift @ARGV;
  65                 last;
  66         }
  67         for my $range (split /,/, $ARGV[0])
  68         {
  69                 if($range =~ /^(\d+)(?:-(\d+|EOF))?$/)
  70                 {
  71                         push @ranges, {'from'=>$1, 'to'=>$2, 'found'=>1};
  72                 }
  73                 else
  74                 {
  75                         die "invalid range: $range\n";
  76                 }
  77         }
  78         shift @ARGV;
  79 }
  80
  81 # load this delayed
  82 eval 'use ARGV::readonly; 1' or die;
  83
  84 $status = 0;
  85
  86 while(<>)
  87 {
  88         if($ARGV ne $prev_ARGV)
  89         {
  90                 $. = 1;
  91                 $status = 2 if any {$_->{'found'} != 1} @ranges;
  92                 map {$_->{'found'} = 0} @ranges;
  93         }
  94         my $include = 0;
  95         for my $range (@ranges)
  96         {
  97                 my $from = $range->{'from'};
  98                 my $to = $range->{'to'};
  99                 if(defined $to)
 100                 {
 101                         if($. >= $from and ($to eq 'EOF' or $. <= $to)) { $range->{'found'} = 1; $include = 1; }
 102                 }
 103                 else
 104                 {
 105                         if($. == $from) { $range->{'found'} = 1; $include = 1; }
 106                 }
 107         }
 108         if($include)
 109         {
 110                 print;
 111         }
 112         $prev_ARGV = $ARGV;
 113 }
 114
 115 $status = 2 if any {$_->{'found'} != 1} @ranges;
 116
 117 exit $status;