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

TWO FOR THE PRICE OF ONE
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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 the perlfunc manpage 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 the perlfunc manpage for details.

Each of these can take a number of targets, which will follow the Number::Compare manpage 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 ( 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 the File::Find::Rule::Extending manpage

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 the File::Find::Rule::Procedural manpage

EXPORTS

find, rule

BUGS

The code relies on qr// compiled regexes, therefore this module requires perl version 5.005_03 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

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