Tuesday, February 10, 2009

Perl: file or directory

To check this, the prescription says:


if (-d $file)
{
   print $file." is a directory\n";
} else {
   print $file." is a file\n";
}


When this is used in pair with IO:Dir, which helps you to enumerate contents of a given directory, one non-obvious step should not be forgotten:


tie %dir, 'IO::Dir', $dir;
foreach my $entry(keys %dir) {
   next if ($entry eq '.' or $entry eq '..');
   # important part is here: concatenation with the full path
   if (-d $dir."/".$entry)
   {
      print $entry." is a directory\n";
   }
}

2 comments:

Dave Sherohman said...

Before declaring $file to be a file, you may also want to test (-f $file) to verify that it is in fact a regular file. Especially if you're on a unix-type system, where it could be a symbolic link, device node, etc. which are neither directories nor (regular) files.

D_K said...

Thanks, Dave, that is an excellent addition.