Problems with -filetest on readdir results

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Wise Elders, I am but a serf on the monastery.. Wine pressing available by request. When I read a directory contents into an array, and test the elements to find directories, it does not return directory values unless the path I am reading from is the local (.) directory. WhatUp with that? If I remove the test, the correct contents are returned, the test just seems to fail.

#!/usr/bin/perl

$path=".";

opendir (DIR, $path) or die "could not open directory";

@files = readdir(DIR);


foreach (@files) {

print  "$_ \n" if (-d $_) ;

          }
[download]

updated by boo_radley :title change

Comment on Problems with -filetest on readdir results Download Code

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Re: Dumb or Cursed? by ides (Deacon) on May 23, 2002 at 18:59 UTC
When using file test operators like -d you need to give it the full path to the file. You might try for instance `print "$_\n" if ( -d "$path/$_" );` [download] ----------------------------------- Frank Wiles <frank@wiles.org> http://frank.wiles.org	[reply] [d/l]
re : Problems with -filetest on readdir results by boo_radley (Parson) on May 23, 2002 at 19:01 UTC
readdir doesn't prepend the path information, you need to do it yourself. something like : `print "$_ \n" if (-d $path.$_);` [download] should do you. This assumes that $path has the appropriate directory separator on the end.	[reply] [d/l]
Re: Problems with -d filetest on readdir results by cjf (Parson) on May 23, 2002 at 19:07 UTC
You need to provide -d with the $path ... `#!/usr/bin/perl -w use strict; my $path = "/usr/bin"; opendir DIR, $path or die "Couldn't read directory: $!"; my @directories = grep { -d "$path/$_" } readdir DIR; closedir DIR; foreach (@directories) { print $_, "\n"; }` [download] Update: Changed $path to "$path/$_" so it prints out only the directories (as opposed to all the files). Thanks to ChemBoy for spotting this and providing the fix.	[reply] [d/l]
Re: Dumb or Cursed? by choocroot (Friar) on May 23, 2002 at 19:07 UTC
The files you get from readdir are relative to your directory $path and -d test for files from the current directory. So, you need to specify your path in the test : `use strict; my $path = "/usr/local/"; opendir( DIR, $path ) or die "could not open dir : $!\n"; my @files = readdir( DIR ); foreach my $file (@files) { print "$file\n" if( -d "$path/$file" ); }` [download]	[reply] [d/l]
Re: Dumb or Cursed? by BazB (Priest) on May 23, 2002 at 18:59 UTC
~~`#!/usr/bin/perl use strict; use warnings; my $path="/foo/bar/"; opendir (DIR, $path) or die "Could not open directory: $!"; @files = readdir(DIR); foreach my $file (@files) { print "$file\n"; }`~~ ~~[download]~~ Your foreach loop was incorrect. Use of strict and warnings also helps spot errors. You could also replace the foreach loop with a map statement: `print map {$_ = "$_\n";} @files;` [download] Cheers! BazB. Update: I ignored the -d test, and obviously don't know my foreach loop from my elbow. Oops. ides++ and boo_radley++	[reply] [d/l] [select]
Problems with -filetest on readdir results by atopolc (Pilgrim) on May 24, 2002 at 03:11 UTC
This is a great opportunity to use map especially if you are going to need the path again later in your script. From your code Untested: `#!/usr/bin/perl $path="."; opendir (DIR, $path) or die "could not open directory"; @files = map {"$path/$_"}, readdir(DIR); #maps the path into your arra +y foreach (@files) { print "$_ \n" if (-d $_) ; }` [download] Update: Thanks merlyn	[reply] [d/l]
•Re: Problems with -filetest on readdir results by merlyn (Sage) on May 24, 2002 at 03:14 UTC
`$path/$_` Why are you dividing a path by the contents of `$_`? Maybe you wanted: `"$path/$_"` [download] -- Randal L. Schwartz, Perl hacker	[reply] [d/l] [select]

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