Re^3: Input Output Question


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Re^3: Input Output Question

by poj (Abbot)

on Jul 15, 2013 at 07:31 UTC ( [id://1044301]=note: print w/replies, xml )

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in reply to Re^2: Input Output Question
in thread Input Output Question

Yes, it just copies the files. If you want to change them in the process then something like this

#!perl
use strict;
opendir(DIR,'../input') or die "$!";
while (readdir DIR){
  unless (/^[.]{1,2}$/){
    print "parsing $_\n";
    open IN,'<','../input/'.$_ 
      or die "Could not open $_ for input : $!";
    open OUT,'>','../output/'.$_ 
      or die "Could not open $_ for output : $!";
    while (my $line = <IN>){
      # process $line
      print OUT $line;
    }
    close IN; close OUT;
  }
}
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poj

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Re^4: Input Output Question
by rjt (Curate) on Jul 15, 2013 at 10:21 UTC

A reasonable approach. I have a couple of comments:

  unless (/^[.]{1,2}$/){
    open IN,'<','../input/'.$_ 
      or die "Could not open $_ for input : $!";
[download]

You skip `.' and `..' with the unless check, but don't do any checks after that, so if DIR contains any other directories, the script will die prematurely. That might not be an issue, depending on the OP's situation, but it's also easily avoided by replacing the unless with:

    next if -d;     # Skip directories.. OR:
  # next unless -f; # Skip anything that isn't a file
[download]

(You can then outdent what is currently in the unless { } block.)

Second, there is pretty much never a good reason not to use indirect filehandles to avoid potential namespace clashes with handles like DIR, IN, and OUT:

open my $in, '<', '../input/' . $_;

Hope this helps.

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