File::Find::Rule

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

"canonpath"

Normalize paths found using "File::Spec−"canonpath>. This will return paths with a file-seperator that is native to your OS (as determined by File::Spec),
instead of the default "/".

For example, this will return "tmp/foobar" on Unix-ish OSes and "tmp\foobar" on Win32.

"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