File::Find::Rule(3)

NAME
File::Find::Rule - Alternative interface to File::Find

SYNOPSIS
  use File::Find::Rule;
  # find all the subdirectories of a given directory
  my @subdirs = File::Find::Rule->directory->in( $directory );

  # find all the .pm files in @INC
  my @files = File::Find::Rule->file()
                              ->name( '*.pm' )
                              ->in( @INC );

  # as above, but without method chaining
  my $rule =  File::Find::Rule->new;
  $rule->file;
  $rule->name( '*.pm' );
  my @files = $rule->in( @INC );

DESCRIPTION
File::Find::Rule is a friendlier interface to File::Find. It allows you to build rules which specify the desired files and directories.

METHODS

"new"
    A constructor. You need not invoke "new" manually unless you wish to, as each of the rule-making methods will auto-create a suitable object if called as class methods.

  Matching Rules

"name( @patterns )"
    Specifies names that should match. May be globs or regular expressions.

     $set->name( '*.mp3', '*.ogg' ); # mp3s or oggs
     $set->name( qr/\.(mp3|ogg)$/ ); # the same as a regex
     $set->name( 'foo.bar' );        # just things named foo.bar

-X tests
    Synonyms are provided for each of the -X tests. See "-X" in perlfunc for details. None of these methods take arguments.

      Test | Method               Test |  Method
     ------|-------------        ------|----------------
       -r  |  readable             -R  |  r_readable
       -w  |  writeable            -W  |  r_writeable
       -w  |  writable             -W  |  r_writable
       -x  |  executable           -X  |  r_executable
       -o  |  owned                -O  |  r_owned
           |                           |
       -e  |  exists               -f  |  file
       -z  |  empty                -d  |  directory
       -s  |  nonempty             -l  |  symlink
           |                       -p  |  fifo
       -u  |  setuid               -S  |  socket
       -g  |  setgid               -b  |  block
       -k  |  sticky               -c  |  character
           |                       -t  |  tty
       -M  |  modified                 |
       -A  |  accessed             -T  |  ascii
       -C  |  changed              -B  |  binary

    Though some tests are fairly meaningless as binary flags ("modified", "accessed", "changed"), they have been included for completeness.

     # find nonempty files
     $rule->file,
          ->nonempty;

stat tests
    The following "stat" based methods are provided: "dev", "ino", "mode", "nlink", "uid", "gid", "rdev", "size", "atime", "mtime", "ctime", "blksize", and "blocks". See "stat" in perlfunc for details.

    Each of these can take a number of targets, which will follow Number::Compare semantics.

     $rule->size( 7 );         # exactly 7
     $rule->size( ">7Ki" );    # larger than 7 * 1024 * 1024 bytes
     $rule->size( ">=7" )
          ->size( "<=90" );    # between 7 and 90, inclusive
     $rule->size( 7, 9, 42 );  # 7, 9 or 42

"any( @rules )"
"or( @rules )"
    Allows shortcircuiting boolean evaluation as an alternative to the default and-like nature of combined rules. "any" and "or" are interchangeable.

     # find avis, movs, things over 200M and empty files
     $rule->any( File::Find::Rule->name( '*.avi', '*.mov' ),
                 File::Find::Rule->size( '>200M' ),
                 File::Find::Rule->file->empty,
               );

"none( @rules )"
"not( @rules )"
    Negates a rule. (The inverse of "any".) "none" and "not" are interchangeable.

      # files that aren't 8.3 safe
      $rule->file
           ->not( $rule->new->name( qr/^[^.]{1,8}(\.[^.]{0,3})?$/ ) );

"prune"
    Traverse no further. This rule always matches.

"discard"
    Don't keep this file. This rule always matches.

"exec( \&subroutine( $shortname, $path, $fullname ) )"
    Allows user-defined rules. Your subroutine will be invoked with $_ set to the current short name, and with parameters of the name, the path you're in, and the full relative filename.

    Return a true value if your rule matched.

     # get things with long names
     $rules->exec( sub { length > 20 } );

"grep( @specifiers )"
    Opens a file and tests it each line at a time.

    For each line it evaluates each of the specifiers, stopping at the first successful match. A specifier may be a regular expression or a subroutine. The subroutine will be invoked with the same parameters as an ->exec subroutine.

    It is possible to provide a set of negative specifiers by enclosing them in anonymous arrays. Should a negative specifier match the iteration is aborted and the clause is failed. For example:

     $rule->grep( qr/^#!.*\bperl/, [ sub { 1 } ] );

    Is a passing clause if the first line of a file looks like a perl shebang line.

"maxdepth( $level )"
    Descend at most $level (a non-negative integer) levels of directories below the starting point.

    May be invoked many times per rule, but only the most recent value is used.

"mindepth( $level )"
    Do not apply any tests at levels less than $level (a non-negative integer).

"extras( \%extras )"
    Specifies extra values to pass through to "File::File::find" as part of the options hash.

    For example this allows you to specify following of symlinks like so:

     my $rule = File::Find::Rule->extras({ follow => 1 });

    May be invoked many times per rule, but only the most recent value is used.

"relative"
    Trim the leading portion of any path found

"not_*"
    Negated version of the rule. An effective shortand related to ! in the procedural interface.

     $foo->not_name('*.pl');

     $foo->not( $foo->new->name('*.pl' ) );

  Query Methods

"in( @directories )"
    Evaluates the rule, returns a list of paths to matching files and directories.

"start( @directories )"
    Starts a find across the specified directories. Matching items may then be queried using "match". This allows you to use a rule as an iterator.

     my $rule = File::Find::Rule->file->name("*.jpeg")->start( "/web" );
     while ( defined ( my $image = $rule->match ) ) {
         ...
     }

"match"
    Returns the next file which matches, false if there are no more.

  Extensions
Extension modules are available from CPAN in the File::Find::Rule namespace. In order to use these extensions either use them directly:

 use File::Find::Rule::ImageSize;
 use File::Find::Rule::MMagic;

 # now your rules can use the clauses supplied by the ImageSize and
 # MMagic extension

or, specify that File::Find::Rule should load them for you:

 use File::Find::Rule qw( :ImageSize :MMagic );

For notes on implementing your own extensions, consult File::Find::Rule::Extending

  Further examples

Finding perl scripts
     my $finder = File::Find::Rule->or
      (
       File::Find::Rule->name( '*.pl' ),
       File::Find::Rule->exec(
                              sub {
                                  if (open my $fh, $_) {
                                      my $shebang = <$fh>;
                                      close $fh;
                                      return $shebang =~ /^#!.*\bperl/;
                                  }
                                  return 0;
                              } ),
      );

    Based upon this message http://use.perl.org/comments.pl?sid=7052&cid=10842

ignore CVS directories
     my $rule = File::Find::Rule->new;
     $rule->or($rule->new
                    ->directory
                    ->name('CVS')
                    ->prune
                    ->discard,
               $rule->new);

    Note here the use of a null rule. Null rules match anything they see, so the effect is to match (and discard) directories called 'CVS' or to match anything.

TWO FOR THE PRICE OF ONE
File::Find::Rule also gives you a procedural interface. This is documented in File::Find::Rule::Procedural

EXPORTS
"find", "rule"

TAINT MODE INTERACTION
As of 0.32 File::Find::Rule doesn't capture the current working directory in a taint-unsafe manner. File::Find itself still does operations that the taint system will flag as insecure but you can use the "extras" feature to ask File::Find to internally "untaint" file paths with a regex like so:

    my $rule = File::Find::Rule->extras({ untaint => 1 });

Please consult File::Find's documentation for "untaint", "untaint_pattern", and "untaint_skip" for more information.

BUGS
The code makes use of the "our" keyword and as such requires perl version 5.6.0 or newer.

Currently it isn't possible to remove a clause from a rule object. If this becomes a significant issue it will be addressed.

AUTHOR
Richard Clamp <richardc@unixbeard.net> with input gained from this use.perl discussion: http://use.perl.org/~richardc/journal/6467

Additional proofreading and input provided by Kake, Greg McCarroll, and Andy Lester andy@petdance.com.

COPYRIGHT
Copyright (C) 2002, 2003, 2004, 2006, 2009, 2011 Richard Clamp. All Rights Reserved.

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

SEE ALSO
File::Find, Text::Glob, Number::Compare, find(1)

If you want to know about the procedural interface, see File::Find::Rule::Procedural, and if you have an idea for a neat extension File::Find::Rule::Extending