12 # can't say 'opendir my $dh, $dirname'
13 # need to initialise $dh
19 use vars qw($VERSION @ISA @EXPORT @EXPORT_OK);
22 @EXPORT = qw(mkpath rmtree);
23 @EXPORT_OK = qw(make_path remove_tree);
25 my $Is_VMS = $^O eq 'VMS';
26 my $Is_MacOS = $^O eq 'MacOS';
28 # These OSes complain if you want to remove a file that you have no
29 # write permission to:
30 my $Force_Writeable = grep {$^O eq $_} qw(amigaos dos epoc MSWin32 MacOS os2);
32 # Unix-like systems need to stat each directory in order to detect
33 # race condition. MS-Windows is immune to this particular attack.
34 my $Need_Stat_Check = !($^O eq 'MSWin32');
52 $object = '' unless defined $object;
53 $message .= ": $!" if $!;
54 push @{${$arg->{error}}}, {$object => $message};
57 _carp(defined($object) ? "$message for $object: $!" : "$message: $!");
62 push @_, {} unless @_ and UNIVERSAL::isa($_[-1],'HASH');
67 my $old_style = !(@_ and UNIVERSAL::isa($_[-1],'HASH'));
74 ($paths, $verbose, $mode) = @_;
75 $paths = [$paths] unless UNIVERSAL::isa($paths,'ARRAY');
76 $arg->{verbose} = $verbose;
77 $arg->{mode} = defined $mode ? $mode : 0777;
81 $arg->{mode} = delete $arg->{mask} if exists $arg->{mask};
82 $arg->{mode} = 0777 unless exists $arg->{mode};
83 ${$arg->{error}} = [] if exists $arg->{error};
86 return _mkpath($arg, $paths);
94 foreach $path (@$paths) {
95 next unless defined($path) and length($path);
96 $path .= '/' if $^O eq 'os2' and $path =~ /^\w:\z/s; # feature of CRT
97 # Logic wants Unix paths, so go with the flow.
100 $path = VMS::Filespec::unixify($path);
103 my $parent = File::Basename::dirname($path);
104 unless (-d $parent or $path eq $parent) {
105 push(@created,_mkpath($arg, [$parent]));
107 print "mkdir $path\n" if $arg->{verbose};
108 if (mkdir($path,$arg->{mode})) {
109 push(@created, $path);
113 my ($e, $e1) = ($save_bang, $^E);
114 $e .= "; $e1" if $e ne $e1;
115 # allow for another process to have created it meanwhile
119 push @{${$arg->{error}}}, {$path => $e};
122 _croak("mkdir $path: $e");
131 push @_, {} unless @_ and UNIVERSAL::isa($_[-1],'HASH');
136 my($dir, $test) = @_;
138 my($dv, $dd) = File::Spec->splitpath($dir, 1);
139 my($tv, $td) = File::Spec->splitpath($test, 1);
142 return 0 if $dv ne $tv;
144 my @d = File::Spec->splitdir($dd);
145 my @t = File::Spec->splitdir($td);
147 # @t can't be a subdir if it's shorter than @d
150 return join('/', @d) eq join('/', splice @t, 0, +@d);
154 my $old_style = !(@_ and UNIVERSAL::isa($_[-1],'HASH'));
160 my ($verbose, $safe);
161 ($paths, $verbose, $safe) = @_;
162 $arg->{verbose} = $verbose;
163 $arg->{safe} = defined $safe ? $safe : 0;
165 if (defined($paths) and length($paths)) {
166 $paths = [$paths] unless UNIVERSAL::isa($paths,'ARRAY');
169 _carp ("No root path(s) specified\n");
175 ${$arg->{error}} = [] if exists $arg->{error};
176 ${$arg->{result}} = [] if exists $arg->{result};
184 $arg->{cwd} = getcwd() or do {
185 _error($arg, "cannot fetch initial working directory");
188 for ($arg->{cwd}) { /\A(.*)\Z/; $_ = $1 } # untaint
190 for my $p (@$paths) {
191 # need to fixup case and map \ to / on Windows
192 my $ortho_root = $^O eq 'MSWin32' ? _slash_lc($p) : $p;
193 my $ortho_cwd = $^O eq 'MSWin32' ? _slash_lc($arg->{cwd}) : $arg->{cwd};
194 my $ortho_root_length = length($ortho_root);
195 $ortho_root_length-- if $^O eq 'VMS'; # don't compare '.' with ']'
196 if ($ortho_root_length && _is_subdir($ortho_root, $ortho_cwd)) {
198 _error($arg, "cannot remove path when cwd is $arg->{cwd}", $p);
203 $p = ":$p" unless $p =~ /:/;
204 $p .= ":" unless $p =~ /:\z/;
206 elsif ($^O eq 'MSWin32') {
212 push @clean_path, $p;
215 @{$arg}{qw(device inode perm)} = (lstat $arg->{cwd})[0,1] or do {
216 _error($arg, "cannot stat initial working directory", $arg->{cwd});
220 return _rmtree($arg, \@clean_path);
228 my $curdir = File::Spec->curdir();
229 my $updir = File::Spec->updir();
233 foreach $root (@$paths) {
234 # since we chdir into each directory, it may not be obvious
235 # to figure out where we are if we generate a message about
236 # a file name. We therefore construct a semi-canonical
237 # filename, anchored from the directory being unlinked (as
238 # opposed to being truly canonical, anchored from the root (/).
240 my $canon = $arg->{prefix}
241 ? File::Spec->catfile($arg->{prefix}, $root)
245 my ($ldev, $lino, $perm) = (lstat $root)[0,1,2] or next ROOT_DIR;
248 $root = VMS::Filespec::pathify($root) if $Is_VMS;
251 # see if we can escalate privileges to get in
252 # (e.g. funny protection mask such as -w- instead of rwx)
254 my $nperm = $perm | 0700;
255 if (!($arg->{safe} or $nperm == $perm or chmod($nperm, $root))) {
256 _error($arg, "cannot make child directory read-write-exec", $canon);
259 elsif (!chdir($root)) {
260 _error($arg, "cannot chdir to child", $canon);
265 my ($cur_dev, $cur_inode, $perm) = (stat $curdir)[0,1,2] or do {
266 _error($arg, "cannot stat current working directory", $canon);
270 if ($Need_Stat_Check) {
271 ($ldev eq $cur_dev and $lino eq $cur_inode)
272 or _croak("directory $canon changed before chdir, expected dev=$ldev ino=$lino, actual dev=$cur_dev ino=$cur_inode, aborting.");
275 $perm &= 07777; # don't forget setuid, setgid, sticky bits
276 my $nperm = $perm | 0700;
278 # notabene: 0700 is for making readable in the first place,
279 # it's also intended to change it to writable in case we have
280 # to recurse in which case we are better than rm -rf for
281 # subtrees with strange permissions
283 if (!($arg->{safe} or $nperm == $perm or chmod($nperm, $curdir))) {
284 _error($arg, "cannot make directory read+writeable", $canon);
289 $d = gensym() if $] < 5.006;
290 if (!opendir $d, $curdir) {
291 _error($arg, "cannot opendir", $canon);
296 if (!defined ${"\cTAINT"} or ${"\cTAINT"}) {
297 # Blindly untaint dir names if taint mode is
298 # active, or any perl < 5.006
299 @files = map { /\A(.*)\z/s; $1 } readdir $d;
308 # Deleting large numbers of files from VMS Files-11
309 # filesystems is faster if done in reverse ASCIIbetical order.
310 # include '.' to '.;' from blead patch #31775
311 @files = map {$_ eq '.' ? '.;' : $_} reverse @files;
312 ($root = VMS::Filespec::unixify($root)) =~ s/\.dir\z//;
315 @files = grep {$_ ne $updir and $_ ne $curdir} @files;
318 # remove the contained files before the directory itself
320 @{$narg}{qw(device inode cwd prefix depth)}
321 = ($cur_dev, $cur_inode, $updir, $canon, $arg->{depth}+1);
322 $count += _rmtree($narg, \@files);
325 # restore directory permissions of required now (in case the rmdir
326 # below fails), while we are still in the directory and may do so
327 # without a race via '.'
328 if ($nperm != $perm and not chmod($perm, $curdir)) {
329 _error($arg, "cannot reset chmod", $canon);
332 # don't leave the client code in an unexpected directory
334 or _croak("cannot chdir to $arg->{cwd} from $canon: $!, aborting.");
336 # ensure that a chdir upwards didn't take us somewhere other
337 # than we expected (see CVE-2002-0435)
338 ($cur_dev, $cur_inode) = (stat $curdir)[0,1]
339 or _croak("cannot stat prior working directory $arg->{cwd}: $!, aborting.");
341 if ($Need_Stat_Check) {
342 ($arg->{device} eq $cur_dev and $arg->{inode} eq $cur_inode)
343 or _croak("previous directory $arg->{cwd} changed before entering $canon, expected dev=$ldev ino=$lino, actual dev=$cur_dev ino=$cur_inode, aborting.");
346 if ($arg->{depth} or !$arg->{keep_root}) {
348 ($Is_VMS ? !&VMS::Filespec::candelete($root) : !-w $root)) {
349 print "skipped $root\n" if $arg->{verbose};
352 if ($Force_Writeable and !chmod $perm | 0700, $root) {
353 _error($arg, "cannot make directory writeable", $canon);
355 print "rmdir $root\n" if $arg->{verbose};
357 push @{${$arg->{result}}}, $root if $arg->{result};
361 _error($arg, "cannot remove directory", $canon);
362 if ($Force_Writeable && !chmod($perm, ($Is_VMS ? VMS::Filespec::fileify($root) : $root))
364 _error($arg, sprintf("cannot restore permissions to 0%o",$perm), $canon);
371 $root = VMS::Filespec::vmsify("./$root")
373 && !File::Spec->file_name_is_absolute($root)
374 && ($root !~ m/(?<!\^)[\]>]+/); # not already in VMS syntax
377 ($Is_VMS ? !&VMS::Filespec::candelete($root)
378 : !(-l $root || -w $root)))
380 print "skipped $root\n" if $arg->{verbose};
384 my $nperm = $perm & 07777 | 0600;
385 if ($Force_Writeable and $nperm != $perm and not chmod $nperm, $root) {
386 _error($arg, "cannot make file writeable", $canon);
388 print "unlink $canon\n" if $arg->{verbose};
389 # delete all versions under VMS
392 push @{${$arg->{result}}}, $root if $arg->{result};
395 _error($arg, "cannot unlink file", $canon);
396 $Force_Writeable and chmod($perm, $root) or
397 _error($arg, sprintf("cannot restore permissions to 0%o",$perm), $canon);
401 last unless $Is_VMS && lstat $root;
409 # fix up slashes and case on MSWin32 so that we can determine that
410 # c:\path\to\dir is underneath C:/Path/To
421 File::Path - Create or remove directory trees
425 This document describes version 2.07 of File::Path, released
430 use File::Path qw(make_path remove_tree);
432 make_path('foo/bar/baz', '/zug/zwang');
433 make_path('foo/bar/baz', '/zug/zwang', {
438 remove_tree('foo/bar/baz', '/zug/zwang');
439 remove_tree('foo/bar/baz', '/zug/zwang', {
441 error => \my $err_list,
444 # legacy (interface promoted before v2.00)
445 mkpath('/foo/bar/baz');
446 mkpath('/foo/bar/baz', 1, 0711);
447 mkpath(['/foo/bar/baz', 'blurfl/quux'], 1, 0711);
448 rmtree('foo/bar/baz', 1, 1);
449 rmtree(['foo/bar/baz', 'blurfl/quux'], 1, 1);
451 # legacy (interface promoted before v2.06)
452 mkpath('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });
453 rmtree('foo/bar/baz', '/zug/zwang', { verbose => 1, mode => 0711 });
457 This module provide a convenient way to create directories of
458 arbitrary depth and to delete an entire directory subtree from the
461 The following functions are provided:
465 =item make_path( $dir1, $dir2, .... )
467 =item make_path( $dir1, $dir2, ...., \%opts )
469 The C<make_path> function creates the given directories if they don't
470 exists before, much like the Unix command C<mkdir -p>.
472 The function accepts a list of directories to be created. Its
473 behaviour may be tuned by an optional hashref appearing as the last
474 parameter on the call.
476 The function returns the list of directories actually created during
477 the call; in scalar context the number of directories created.
479 The following keys are recognised in the option hash:
485 The numeric permissions mode to apply to each created directory
486 (defaults to 0777), to be modified by the current C<umask>. If the
487 directory already exists (and thus does not need to be created),
488 the permissions will not be modified.
490 C<mask> is recognised as an alias for this parameter.
492 =item verbose => $bool
494 If present, will cause C<make_path> to print the name of each directory
495 as it is created. By default nothing is printed.
499 If present, it should be a reference to a scalar.
500 This scalar will be made to reference an array, which will
501 be used to store any errors that are encountered. See the L</"ERROR
502 HANDLING"> section for more information.
504 If this parameter is not used, certain error conditions may raise
505 a fatal error that will cause the program will halt, unless trapped
512 =item mkpath( $dir, $verbose, $mode )
514 =item mkpath( [$dir1, $dir2,...], $verbose, $mode )
516 =item mkpath( $dir1, $dir2,..., \%opt )
518 The mkpath() function provide the legacy interface of make_path() with
519 a different interpretation of the arguments passed. The behaviour and
520 return value of the function is otherwise identical to make_path().
522 =item remove_tree( $dir1, $dir2, .... )
524 =item remove_tree( $dir1, $dir2, ...., \%opts )
526 The C<remove_tree> function deletes the given directories and any
527 files and subdirectories they might contain, much like the Unix
528 command C<rm -r> or C<del /s> on Windows.
530 The function accepts a list of directories to be
531 removed. Its behaviour may be tuned by an optional hashref
532 appearing as the last parameter on the call.
534 The functions returns the number of files successfully deleted.
536 The following keys are recognised in the option hash:
540 =item verbose => $bool
542 If present, will cause C<remove_tree> to print the name of each file as
543 it is unlinked. By default nothing is printed.
547 When set to a true value, will cause C<remove_tree> to skip the files
548 for which the process lacks the required privileges needed to delete
549 files, such as delete privileges on VMS. In other words, the code
550 will make no attempt to alter file permissions. Thus, if the process
551 is interrupted, no filesystem object will be left in a more
554 =item keep_root => $bool
556 When set to a true value, will cause all files and subdirectories
557 to be removed, except the initially specified directories. This comes
558 in handy when cleaning out an application's scratch directory.
560 remove_tree( '/tmp', {keep_root => 1} );
562 =item result => \$res
564 If present, it should be a reference to a scalar.
565 This scalar will be made to reference an array, which will
566 be used to store all files and directories unlinked
567 during the call. If nothing is unlinked, the array will be empty.
569 remove_tree( '/tmp', {result => \my $list} );
570 print "unlinked $_\n" for @$list;
572 This is a useful alternative to the C<verbose> key.
576 If present, it should be a reference to a scalar.
577 This scalar will be made to reference an array, which will
578 be used to store any errors that are encountered. See the L</"ERROR
579 HANDLING"> section for more information.
581 Removing things is a much more dangerous proposition than
582 creating things. As such, there are certain conditions that
583 C<remove_tree> may encounter that are so dangerous that the only
584 sane action left is to kill the program.
586 Use C<error> to trap all that is reasonable (problems with
587 permissions and the like), and let it die if things get out
588 of hand. This is the safest course of action.
594 =item rmtree( $dir, $verbose, $safe )
596 =item rmtree( [$dir1, $dir2,...], $verbose, $safe )
598 =item rmtree( $dir1, $dir2,..., \%opt )
600 The rmtree() function provide the legacy interface of remove_tree()
601 with a different interpretation of the arguments passed. The behaviour
602 and return value of the function is otherwise identical to
607 =head2 ERROR HANDLING
613 The following error handling mechanism is considered
614 experimental and is subject to change pending feedback from
619 If C<make_path> or C<remove_tree> encounter an error, a diagnostic
620 message will be printed to C<STDERR> via C<carp> (for non-fatal
621 errors), or via C<croak> (for fatal errors).
623 If this behaviour is not desirable, the C<error> attribute may be
624 used to hold a reference to a variable, which will be used to store
625 the diagnostics. The variable is made a reference to an array of hash
626 references. Each hash contain a single key/value pair where the key
627 is the name of the file, and the value is the error message (including
628 the contents of C<$!> when appropriate). If a general error is
629 encountered the diagnostic key will be empty.
631 An example usage looks like:
633 remove_tree( 'foo/bar', 'bar/rat', {error => \my $err} );
635 for my $diag (@$err) {
636 my ($file, $message) = %$diag;
638 print "general error: $message\n";
641 print "problem unlinking $file: $message\n";
646 print "No error encountered\n";
649 Note that if no errors are encountered, C<$err> will reference an
650 empty array. This means that C<$err> will always end up TRUE; so you
651 need to test C<@$err> to determine if errors occured.
655 C<File::Path> blindly exports C<mkpath> and C<rmtree> into the
656 current namespace. These days, this is considered bad style, but
657 to change it now would break too much code. Nonetheless, you are
658 invited to specify what it is you are expecting to use:
660 use File::Path 'rmtree';
662 The routines C<make_path> and C<remove_tree> are B<not> exported
663 by default. You must specify which ones you want to use.
665 use File::Path 'remove_tree';
667 Note that a side-effect of the above is that C<mkpath> and C<rmtree>
668 are no longer exported at all. This is due to the way the C<Exporter>
669 module works. If you are migrating a codebase to use the new
670 interface, you will have to list everything explicitly. But that's
671 just good practice anyway.
673 use File::Path qw(remove_tree rmtree);
675 =head3 SECURITY CONSIDERATIONS
677 There were race conditions 1.x implementations of File::Path's
678 C<rmtree> function (although sometimes patched depending on the OS
679 distribution or platform). The 2.0 version contains code to avoid the
680 problem mentioned in CVE-2002-0435.
682 See the following pages for more information:
684 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=286905
685 http://www.nntp.perl.org/group/perl.perl5.porters/2005/01/msg97623.html
686 http://www.debian.org/security/2005/dsa-696
688 Additionally, unless the C<safe> parameter is set (or the
689 third parameter in the traditional interface is TRUE), should a
690 C<remove_tree> be interrupted, files that were originally in read-only
691 mode may now have their permissions set to a read-write (or "delete
696 FATAL errors will cause the program to halt (C<croak>), since the
697 problem is so severe that it would be dangerous to continue. (This
698 can always be trapped with C<eval>, but it's not a good idea. Under
699 the circumstances, dying is the best thing to do).
701 SEVERE errors may be trapped using the modern interface. If the
702 they are not trapped, or the old interface is used, such an error
703 will cause the program will halt.
705 All other errors may be trapped using the modern interface, otherwise
706 they will be C<carp>ed about. Program execution will not be halted.
710 =item mkdir [path]: [errmsg] (SEVERE)
712 C<make_path> was unable to create the path. Probably some sort of
713 permissions error at the point of departure, or insufficient resources
714 (such as free inodes on Unix).
716 =item No root path(s) specified
718 C<make_path> was not given any paths to create. This message is only
719 emitted if the routine is called with the traditional interface.
720 The modern interface will remain silent if given nothing to do.
722 =item No such file or directory
724 On Windows, if C<make_path> gives you this warning, it may mean that
725 you have exceeded your filesystem's maximum path length.
727 =item cannot fetch initial working directory: [errmsg]
729 C<remove_tree> attempted to determine the initial directory by calling
730 C<Cwd::getcwd>, but the call failed for some reason. No attempt
731 will be made to delete anything.
733 =item cannot stat initial working directory: [errmsg]
735 C<remove_tree> attempted to stat the initial directory (after having
736 successfully obtained its name via C<getcwd>), however, the call
737 failed for some reason. No attempt will be made to delete anything.
739 =item cannot chdir to [dir]: [errmsg]
741 C<remove_tree> attempted to set the working directory in order to
742 begin deleting the objects therein, but was unsuccessful. This is
743 usually a permissions issue. The routine will continue to delete
744 other things, but this directory will be left intact.
746 =item directory [dir] changed before chdir, expected dev=[n] ino=[n], actual dev=[n] ino=[n], aborting. (FATAL)
748 C<remove_tree> recorded the device and inode of a directory, and then
749 moved into it. It then performed a C<stat> on the current directory
750 and detected that the device and inode were no longer the same. As
751 this is at the heart of the race condition problem, the program
752 will die at this point.
754 =item cannot make directory [dir] read+writeable: [errmsg]
756 C<remove_tree> attempted to change the permissions on the current directory
757 to ensure that subsequent unlinkings would not run into problems,
758 but was unable to do so. The permissions remain as they were, and
759 the program will carry on, doing the best it can.
761 =item cannot read [dir]: [errmsg]
763 C<remove_tree> tried to read the contents of the directory in order
764 to acquire the names of the directory entries to be unlinked, but
765 was unsuccessful. This is usually a permissions issue. The
766 program will continue, but the files in this directory will remain
769 =item cannot reset chmod [dir]: [errmsg]
771 C<remove_tree>, after having deleted everything in a directory, attempted
772 to restore its permissions to the original state but failed. The
773 directory may wind up being left behind.
775 =item cannot remove [dir] when cwd is [dir]
777 The current working directory of the program is F</some/path/to/here>
778 and you are attempting to remove an ancestor, such as F</some/path>.
779 The directory tree is left untouched.
781 The solution is to C<chdir> out of the child directory to a place
782 outside the directory tree to be removed.
784 =item cannot chdir to [parent-dir] from [child-dir]: [errmsg], aborting. (FATAL)
786 C<remove_tree>, after having deleted everything and restored the permissions
787 of a directory, was unable to chdir back to the parent. The program
788 halts to avoid a race condition from occurring.
790 =item cannot stat prior working directory [dir]: [errmsg], aborting. (FATAL)
792 C<remove_tree> was unable to stat the parent directory after have returned
793 from the child. Since there is no way of knowing if we returned to
794 where we think we should be (by comparing device and inode) the only
795 way out is to C<croak>.
797 =item previous directory [parent-dir] changed before entering [child-dir], expected dev=[n] ino=[n], actual dev=[n] ino=[n], aborting. (FATAL)
799 When C<remove_tree> returned from deleting files in a child directory, a
800 check revealed that the parent directory it returned to wasn't the one
801 it started out from. This is considered a sign of malicious activity.
803 =item cannot make directory [dir] writeable: [errmsg]
805 Just before removing a directory (after having successfully removed
806 everything it contained), C<remove_tree> attempted to set the permissions
807 on the directory to ensure it could be removed and failed. Program
808 execution continues, but the directory may possibly not be deleted.
810 =item cannot remove directory [dir]: [errmsg]
812 C<remove_tree> attempted to remove a directory, but failed. This may because
813 some objects that were unable to be removed remain in the directory, or
814 a permissions issue. The directory will be left behind.
816 =item cannot restore permissions of [dir] to [0nnn]: [errmsg]
818 After having failed to remove a directory, C<remove_tree> was unable to
819 restore its permissions from a permissive state back to a possibly
820 more restrictive setting. (Permissions given in octal).
822 =item cannot make file [file] writeable: [errmsg]
824 C<remove_tree> attempted to force the permissions of a file to ensure it
825 could be deleted, but failed to do so. It will, however, still attempt
828 =item cannot unlink file [file]: [errmsg]
830 C<remove_tree> failed to remove a file. Probably a permissions issue.
832 =item cannot restore permissions of [file] to [0nnn]: [errmsg]
834 After having failed to remove a file, C<remove_tree> was also unable
835 to restore the permissions on the file to a possibly less permissive
836 setting. (Permissions given in octal).
848 Allows files and directories to be moved to the Trashcan/Recycle
849 Bin (where they may later be restored if necessary) if the operating
850 system supports such functionality. This feature may one day be
851 made available directly in C<File::Path>.
857 When removing directory trees, if you want to examine each file to
858 decide whether to delete it (and possibly leaving large swathes
859 alone), F<File::Find::Rule> offers a convenient and flexible approach
860 to examining directory trees.
866 Please report all bugs on the RT queue:
868 L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=File-Path>
870 =head1 ACKNOWLEDGEMENTS
872 Paul Szabo identified the race condition originally, and Brendan
873 O'Dea wrote an implementation for Debian that addressed the problem.
874 That code was used as a basis for the current code. Their efforts
875 are greatly appreciated.
877 Gisle Aas made a number of improvements to the documentation for
878 2.07 and his advice and assistance is also greatly appreciated.
882 Tim Bunce and Charles Bailey. Currently maintained by David Landgren
883 <F<david@landgren.net>>.
887 This module is copyright (C) Charles Bailey, Tim Bunce and
888 David Landgren 1995-2008. All rights reserved.
892 This library is free software; you can redistribute it and/or modify
893 it under the same terms as Perl itself.