Rafaël Garcia-Suarez > perl-5.9.5 > File::Path

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By perlmonks.org
Module Version: 2.01   Source  

NAME ^

File::Path - Create or remove directory trees

VERSION ^

This document describes version 2.01 of File::Path, released 2007-06-27.

SYNOPSIS ^

    use File::Path;

    # modern
    mkpath( 'foo/bar/baz', '/zug/zwang', {verbose => 1} );

    rmtree(
        'foo/bar/baz', '/zug/zwang',
        { verbose => 1, error  => \my $err_list }
    );

    # traditional
    mkpath(['/foo/bar/baz', 'blurfl/quux'], 1, 0711);
    rmtree(['foo/bar/baz', 'blurfl/quux'], 1, 1);

DESCRIPTION ^

The mkpath function provides a convenient way to create directories, even if your mkdir kernel call won't create more than one level of directory at a time. Similarly, the rmtree function provides a convenient way to delete a subtree from the directory structure, much like the Unix command rm -r.

Both functions may be called in one of two ways, the traditional, compatible with code written since the dawn of time, and modern, that offers a more flexible and readable idiom. New code should use the modern interface.

FUNCTIONS

The modern way of calling mkpath and rmtree is with an optional hash reference at the end of the parameter list that holds various keys that can be used to control the function's behaviour, following a plain list of directories upon which to operate.

mkpath

The following keys are recognised as as parameters to mkpath. It returns the list of files actually created during the call.

  my @created = mkpath(
    qw(/tmp /flub /home/nobody),
    {verbose => 1, mode => 0750},
  );
  print "created $_\n" for @created;
mode

The numeric mode to use when creating the directories (defaults to 07777), to be modified by the current umask. (mask is recognised as an alias for this parameter).

verbose

If present, will cause mkpath to print the name of each directory as it is created. By default nothing is printed.

error

If present, will be interpreted as a reference to a list, and will be used to store any errors that are encountered. See the ERROR HANDLING section below to find out more.

If this parameter is not used, any errors encountered will raise a fatal error that need to be trapped in an eval block, or the program will halt.

rmtree

verbose

If present, will cause rmtree to print the name of each file as it is unlinked. By default nothing is printed.

skip_others

When set to a true value, will cause rmtree to skip any files to which you do not have delete access (if running under VMS) or write access (if running under another OS). This will change in the future when a criterion for 'delete permission' under OSs other than VMS is settled.

keep_root

When set to a true value, will cause everything except the specified base directories to be unlinked. This comes in handy when cleaning out an application's scratch directory.

  rmtree( '/tmp', {keep_root => 1} );
result

If present, will be interpreted as a reference to a list, and will be used to store the list of all files and directories unlinked during the call. If nothing is unlinked, a reference to an empty list is returned (rather than undef).

  rmtree( '/tmp', {result => \my $list} );
  print "unlinked $_\n" for @$list;
error

If present, will be interpreted as a reference to a list, and will be used to store any errors that are encountered. See the ERROR HANDLING section below to find out more.

If this parameter is not used, any errors encountered will raise a fatal error that need to be trapped in an eval block, or the program will halt.

TRADITIONAL INTERFACE

The old interface for mkpath and rmtree take a reference to a list of directories (to create or remove), followed by a series of positional numeric modal parameters that control their behaviour.

This design made it difficult to add additional functionality, as well as posed the problem of what to do when you don't care how the initial positional parameters are specified but only the last one needs to be specified. The calls themselves are also less self-documenting.

mkpath takes three arguments:

It returns a list of all directories (including intermediates, determined using the Unix '/' separator) created. In scalar context it returns the number of directories created.

If a system error prevents a directory from being created, then the mkpath function throws a fatal error with Carp::croak. This error can be trapped with an eval block:

  eval { mkpath($dir) };
  if ($@) {
    print "Couldn't create $dir: $@";
  }

In the traditional form, rmtree takes three arguments:

It returns the number of files, directories and symlinks successfully deleted. Symlinks are simply deleted and not followed.

Note also that the occurrence of errors in rmtree using the traditional interface can be determined only by trapping diagnostic messages using $SIG{__WARN__}; it is not apparent from the return value. (The modern interface may use the error parameter to record any problems encountered.

ERROR HANDLING

If mkpath or rmtree encounter an error, a diagnostic message will be printed to STDERR via carp (for non-fatal errors), or via croak (for fatal errors).

If this behaviour is not desirable, the error attribute may be used to hold a reference to a variable, which will be used to store the diagnostics. The result is a reference to a list of hash references. For each hash reference, the key is the name of the file, and the value is the error message (usually the contents of $!). An example usage looks like:

  rmpath( 'foo/bar', 'bar/rat', {error => \my $err} );
  for my $diag (@$err) {
    my ($file, $message) = each %$diag;
    print "problem unlinking $file: $message\n";
  }

If no errors are encountered, $err will point to an empty list (thus there is no need to test for undef). If a general error is encountered (for instance, rmtree attempts to remove a directory tree that does not exist), the diagnostic key will be empty, only the value will be set:

  rmpath( '/no/such/path', {error => \my $err} );
  for my $diag (@$err) {
    my ($file, $message) = each %$diag;
    if ($file eq '') {
      print "general error: $message\n";
    }
  }

NOTES

HEURISTICS

The functions detect (as far as possible) which way they are being called and will act appropriately. It is important to remember that the heuristic for detecting the old style is either the presence of an array reference, or two or three parameters total and second and third parameters are numeric. Hence...

    mkpath '486', '487', '488';

... will not assume the modern style and create three directories, rather it will create one directory verbosely, setting the permission to 0750 (488 being the decimal equivalent of octal 750). Here, old style trumps new. It must, for backwards compatibility reasons.

If you want to ensure there is absolutely no ambiguity about which way the function will behave, make sure the first parameter is a reference to a one-element list, to force the old style interpretation:

    mkpath ['486'], '487', '488';

and get only one directory created. Or add a reference to an empty parameter hash, to force the new style:

    mkpath '486', '487', '488', {};

... and hence create the three directories. If the empty hash reference seems a little strange to your eyes, or you suspect a subsequent programmer might helpfully optimise it away, you can add a parameter set to a default value:

    mkpath '486', '487', '488', {verbose => 0};

RACE CONDITIONS

There are race conditions internal to the implementation of rmtree making it unsafe to use on directory trees which may be altered or moved while rmtree is running, and in particular on any directory trees with any path components or subdirectories potentially writable by untrusted users.

Additionally, if the skip_others parameter is not set (or the third parameter in the traditional inferface is not TRUE) and rmtree is interrupted, it may leave files and directories with permissions altered to allow deletion.

File::Path blindly exports mkpath and rmtree into the current namespace. These days, this is considered bad style, but to change it now would break too much code. Nonetheless, you are invited to specify what it is you are expecting to use:

  use File::Path 'rmtree';

DIAGNOSTICS ^

SEE ALSO ^

BUGS ^

Please report all bugs on the RT queue:

http://rt.cpan.org/NoAuth/Bugs.html?Dist=File-Path

AUTHORS ^

Tim Bunce <Tim.Bunce@ig.co.uk> and Charles Bailey <bailey@newman.upenn.edu>.

Currently maintained by David Landgren <david@landgren.net>.

COPYRIGHT ^

This module is copyright (C) Charles Bailey, Tim Bunce and David Landgren 1995-2007. All rights reserved.

LICENSE ^

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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