1File::chmod(3) User Contributed Perl Documentation File::chmod(3)
2
6 File::chmod - Implements symbolic and ls chmod modes
7
9 version 0.42
10
12 use File::chmod;
13 $File::chmod::UMASK = 0;
14 # It is recommended that you explicitly set $File::chmod::UMASK
15 # as the default will change in the future
16 #
17 # 0 is recommended to behave like system chmod
18 # 1 if you want File::chmod to apply your environment set umask.
19 # 2 is how we detect that it's internally set, undef will become the
20 # default in the future, eventually a lexicaly scoped API may be designed
21 # chmod takes all three types
23 # these all do the same thing
24 chmod(0666,@files);
25 chmod("=rw",@files);
26 chmod("-rw-rw-rw-",@files);
27 # or
29 use File::chmod qw( symchmod lschmod );
31 chmod(0666,@files); # this is the normal chmod
33 symchmod("=rw",@files); # takes symbolic modes only
34 lschmod("-rw-rw-rw-",@files); # takes "ls" modes only
35 # more functions, read on to understand
37
39 File::chmod is a utility that allows you to bypass system calls or bit
40 processing of a file's permissions. It overloads the chmod() function
41 with its own that gets an octal mode, a symbolic mode (see below), or
42 an "ls" mode (see below). If you wish not to overload chmod(), you can
43 export symchmod() and lschmod(), which take, respectively, a symbolic
44 mode and an "ls" mode.
45 An added feature to version 0.30 is the $UMASK variable, explained in
47 detail below; if "symchmod()" is called and this variable is true, then
48 the function uses the (also new) $MASK variable (which defaults to
49 "umask()") as a mask against the new mode. This mode is on by default,
50 and changes the behavior from what you would expect if you are used to
51 UNIX "chmod". This may change in the future.
52 Symbolic modes are thoroughly described in your chmod(1) man page, but
54 here are a few examples.
55 chmod("+x","file1","file2"); # overloaded chmod(), that is...
57 # turns on the execute bit for all users on those two files
58 chmod("o=,g-w","file1","file2");
60 # removes 'other' permissions, and the write bit for 'group'
61 chmod("=u","file1","file2");
63 # sets all bits to those in 'user'
64 "ls" modes are the type produced on the left-hand side of an "ls -l" on
66 a directory. Examples are:
67 chmod("-rwxr-xr-x","file1","file2");
69 # the 0755 setting; user has read-write-execute, group and others
70 # have read-execute priveleges
71 chmod("-rwsrws---","file1","file2");
73 # sets read-write-execute for user and group, none for others
74 # also sets set-uid and set-gid bits
75 The regular chmod() and lschmod() are absolute; that is, they are not
77 appending to or subtracting from the current file mode. They set it,
78 regardless of what it had been before. symchmod() is useful for
79 allowing the modifying of a file's permissions without having to run a
80 system call or determining the file's permissions, and then combining
81 that with whatever bits are appropriate. It also operates separately
82 on each file.
83
85 chmod(MODE,FILES)
86 Takes an octal, symbolic, or "ls" mode, and then chmods each file
87 appropriately.
88 getchmod(MODE,FILES)
90 Returns a list of modified permissions, without chmodding files.
91 Accepts any of the three kinds of modes.
92 @newmodes = getchmod("+x","file1","file2");
94 # @newmodes holds the octal permissions of the files'
95 # modes, if they were to be sent through chmod("+x"...)
96
98 symchmod(MODE,FILES)
99 Takes a symbolic permissions mode, and chmods each file.
100 lschmod(MODE,FILES)
102 Takes an "ls" permissions mode, and chmods each file.
103 getsymchmod(MODE,FILES)
105 Returns a list of modified permissions, without chmodding files.
106 Accepts only symbolic permission modes.
107 getlschmod(MODE,FILES)
109 Returns a list of modified permissions, without chmodding files.
110 Accepts only "ls" permission modes.
111 getmod(FILES)
113 Returns a list of the current mode of each file.
114
116 $File::chmod::DEBUG
117 If set to a true value, it will report warnings, similar to those
118 produced by chmod() on your system. Otherwise, the functions will not
119 report errors. Example: a file can not have file-locking and the set-
120 gid bits on at the same time. If $File::chmod::DEBUG is true, the
121 function will report an error. If not, you are not warned of the
122 conflict. It is set to 1 as default.
123 $File::chmod::MASK
125 Contains the umask to apply to new file modes when using getsymchmod().
126 This defaults to the return value of umask() at compile time. Is only
127 applied if $UMASK is true.
128 $File::chmod::UMASK
130 This is a boolean which tells getsymchmod() whether or not to apply the
131 umask found in $MASK. It defaults to true.
132
134 This is only good on Unix-like boxes. I would like people to help me
135 work on File::chmod for any OS that deserves it. If you would like to
136 help, please email me (address below) with the OS and any information
137 you might have on how chmod() should work on it; if you don't have any
138 specific information, but would still like to help, hey, that's good
139 too. I have the following information (from "perlport"):
140 Win32
142 Only good for changing "owner" read-write access, "group", and
143 "other" bits are meaningless. NOTE: Win32::File and
144 Win32::FileSecurity already do this. I do not currently see a need
145 to port File::chmod.
146 MacOS
148 Only limited meaning. Disabling/enabling write permission is mapped
149 to locking/unlocking the file.
150 RISC OS
152 Only good for changing "owner" and "other" read-write access.
153
155 Stat::lsMode (by Mark-James Dominus, CPAN ID: MJD)
156 chmod(1) manpage
157 perldoc -f chmod
158 perldoc -f stat
159
161 Please report any bugs or feature requests on the bugtracker website
162 https://github.com/xenoterracide/file-chmod/issues
163 When submitting a bug or request, please include a test-file or a patch
165 to an existing test-file that illustrates the bug or desired feature.
166
168 • David Steinbrunner <dsteinbrunner@pobox.com>
169 • Slaven Rezic <slaven@rezic.de>
171 • Steve Throckmorton <arrestee@gmail.com>
173 • Tim <oylenshpeegul@gmail.com>
175
177 • Jeff Pinyan <japhy.734+CPAN@gmail.com>
178 • Caleb Cushing <xenoterracide@gmail.com>
180
182 This software is copyright (c) 2015 by Caleb Cushing and Jeff Pinyan.
183 This is free software; you can redistribute it and/or modify it under
185 the same terms as the Perl 5 programming language system itself.
186perl v5.36.0 2022-07-22 File::chmod(3)