How can I create a directory if one doesn't exist using Perl?

Question

Currently, my Perl output is hard-coded to dump into the following Unix directory:

my $stat_dir = "/home/courses/" . **NEED DIR VAR HERE**;

The filename is built as such:

$stat_file = $stat_dir . "/" . $sess.substr($yr, 2, 2) . "_COURSES.csv";

I need a similar approach to building Unix directories, but I need to check if they exist first before creating them.

How can I do auto-numbering (revisions) of the $stat_file so that when these files get pumped into the same directory, they do not overwrite or append to existing files in the directory?

brian d foy · Accepted Answer · 2014-09-17 09:28:13Z

19

Erm... mkdir $stat_dir unless -d $stat_dir?

It really doesn't seem like a good idea to embed 'extra' questions like that.

edited Sep 17, 2014 at 9:28

brian d foy

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answered Mar 31, 2009 at 15:11

chaos

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1 Comment

CheeseConQueso Over a year ago

I kind of agree, but figured they are a good package deal to know when trying to do this kind of stuff.

brian d foy · Accepted Answer · 2014-09-17 09:28:59Z

14

Use the -d operator and File::Path.

use File::Path qw(make_path);
eval { make_path($dir) };
if ($@) {
  print "Couldn't create $dir: $@";
}

make_path has an advantage over mkdir in that it can create trees of arbitrary depth.

And use -e to check file exists

my $fileSuffix = 0;
while (-e $filename) {
    $filename = $filePrefix . ++$fileSuffix . $fileExtension;
}

edited Sep 17, 2014 at 9:28

brian d foy

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answered Mar 31, 2009 at 15:11

Ed Guiness

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2 Comments

daotoad Over a year ago

Checking $@ is unreliable. Use eval{mkpath($dir); 1} or do { warn "badness\n" }. See search.cpan.org/dist/Acme-ExceptionEater/lib/Acme/… for an example of why checking $@ is bad.

kyle Over a year ago

As of v2.09(2013-01) it appears that it is now make_path

Peter Mortensen · Accepted Answer · 2018-04-25 18:03:56Z

7

Remember the directory's -d existence doesn't mean -w writable. But assuming you're in a personal area the mkdir($dir) unless(-d $dir) would work fine.

edited Apr 25, 2018 at 18:03

Peter Mortensen

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answered Mar 31, 2009 at 15:26

hpavc

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Comments

brian d foy · Accepted Answer · 2014-09-17 09:27:39Z

3

Perl has a built-in function mkdir

Take a look at perldoc perlfunc or the mkdir program from Perl Power Tools.

I believe it is safe to create a directory that already exists, take a look at the docs.

edited Sep 17, 2014 at 9:27

brian d foy

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answered Mar 31, 2009 at 15:13

fido

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