1CHOWN(1P) POSIX Programmer's Manual CHOWN(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 chown - change the file ownership
13
15 chown [-hR] owner[:group] file ...
16 chown -R [-H | -L | -P ] owner[:group] file ...
18
21 The chown utility shall set the user ID of the file named by each file
22 operand to the user ID specified by the owner operand.
23 For each file operand, or, if the -R option is used, each file encoun‐
25 tered while walking the directory trees specified by the file operands,
26 the chown utility shall perform actions equivalent to the chown() func‐
27 tion defined in the System Interfaces volume of IEEE Std 1003.1-2001,
28 called with the following arguments:
29 1. The file operand shall be used as the path argument.
31 2. The user ID indicated by the owner portion of the first operand
33 shall be used as the owner argument.
34 3. If the group portion of the first operand is given, the group ID
36 indicated by it shall be used as the group argument; otherwise, the
37 group ownership shall not be changed.
38 Unless chown is invoked by a process with appropriate privileges, the
40 set-user-ID and set-group-ID bits of a regular file shall be cleared
41 upon successful completion; the set-user-ID and set-group-ID bits of
42 other file types may be cleared.
43
45 The chown utility shall conform to the Base Definitions volume of
46 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
47 The following options shall be supported by the implementation:
49 -h If the system supports user IDs for symbolic links, for each
51 file operand that names a file of type symbolic link, chown
52 shall attempt to set the user ID of the symbolic link. If the
53 system supports group IDs for symbolic links, and a group ID was
54 specified, for each file operand that names a file of type sym‐
55 bolic link, chown shall attempt to set the group ID of the sym‐
56 bolic link. If the system does not support user or group IDs for
57 symbolic links, for each file operand that names a file of type
58 symbolic link, chown shall do nothing more with the current file
59 and shall go on to any remaining files.
60 -H If the -R option is specified and a symbolic link referencing a
62 file of type directory is specified on the command line, chown
63 shall change the user ID (and group ID, if specified) of the
64 directory referenced by the symbolic link and all files in the
65 file hierarchy below it.
66 -L If the -R option is specified and a symbolic link referencing a
68 file of type directory is specified on the command line or
69 encountered during the traversal of a file hierarchy, chown
70 shall change the user ID (and group ID, if specified) of the
71 directory referenced by the symbolic link and all files in the
72 file hierarchy below it.
73 -P If the -R option is specified and a symbolic link is specified
75 on the command line or encountered during the traversal of a
76 file hierarchy, chown shall change the owner ID (and group ID,
77 if specified) of the symbolic link if the system supports this
78 operation. The chown utility shall not follow the symbolic link
79 to any other part of the file hierarchy.
80 -R Recursively change file user and group IDs. For each file oper‐
82 and that names a directory, chown shall change the user ID (and
83 group ID, if specified) of the directory and all files in the
84 file hierarchy below it. Unless a -H, -L, or -P option is speci‐
85 fied, it is unspecified which of these options will be used as
86 the default.
87 Specifying more than one of the mutually-exclusive options -H, -L, and
90 -P shall not be considered an error. The last option specified shall
91 determine the behavior of the utility.
92
94 The following operands shall be supported:
95 owner[:group]
97 A user ID and optional group ID to be assigned to file. The
98 owner portion of this operand shall be a user name from the user
99 database or a numeric user ID. Either specifies a user ID which
100 shall be given to each file named by one of the file operands.
101 If a numeric owner operand exists in the user database as a user
102 name, the user ID number associated with that user name shall be
103 used as the user ID. Similarly, if the group portion of this op‐
104 erand is present, it shall be a group name from the group data‐
105 base or a numeric group ID. Either specifies a group ID which
106 shall be given to each file. If a numeric group operand exists
107 in the group database as a group name, the group ID number asso‐
108 ciated with that group name shall be used as the group ID.
109 file A pathname of a file whose user ID is to be modified.
111
114 Not used.
115
117 None.
118
120 The following environment variables shall affect the execution of
121 chown:
122 LANG Provide a default value for the internationalization variables
124 that are unset or null. (See the Base Definitions volume of
125 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
126 ables for the precedence of internationalization variables used
127 to determine the values of locale categories.)
128 LC_ALL If set to a non-empty string value, override the values of all
130 the other internationalization variables.
131 LC_CTYPE
133 Determine the locale for the interpretation of sequences of
134 bytes of text data as characters (for example, single-byte as
135 opposed to multi-byte characters in arguments).
136 LC_MESSAGES
138 Determine the locale that should be used to affect the format
139 and contents of diagnostic messages written to standard error.
140 NLSPATH
142 Determine the location of message catalogs for the processing of
143 LC_MESSAGES .
144
147 Default.
148
150 Not used.
151
153 The standard error shall be used only for diagnostic messages.
154
156 None.
157
159 None.
160
162 The following exit values shall be returned:
163 0 The utility executed successfully and all requested changes were
165 made.
166 >0 An error occurred.
168
171 Default.
172 The following sections are informative.
174
176 Only the owner of a file or the user with appropriate privileges may
177 change the owner or group of a file.
178 Some implementations restrict the use of chown to a user with appropri‐
180 ate privileges.
181
183 None.
184
186 The System V and BSD versions use different exit status codes. Some
187 implementations used the exit status as a count of the number of errors
188 that occurred; this practice is unworkable since it can overflow the
189 range of valid exit status values. These are masked by specifying only
190 0 and >0 as exit values.
191 The functionality of chown is described substantially through refer‐
193 ences to functions in the System Interfaces volume of
194 IEEE Std 1003.1-2001. In this way, there is no duplication of effort
195 required for describing the interactions of permissions, multiple
196 groups, and so on.
197 The 4.3 BSD method of specifying both owner and group was included in
199 this volume of IEEE Std 1003.1-2001 because:
200 * There are cases where the desired end condition could not be
202 achieved using the chgrp and chown (that only changed the user ID)
203 utilities. (If the current owner is not a member of the desired
204 group and the desired owner is not a member of the current group,
205 the chown() function could fail unless both owner and group are
206 changed at the same time.)
207 * Even if they could be changed independently, in cases where both are
209 being changed, there is a 100% performance penalty caused by being
210 forced to invoke both utilities.
211 The BSD syntax user[. group] was changed to user[: group] in this vol‐
213 ume of IEEE Std 1003.1-2001 because the period is a valid character in
214 login names (as specified by the Base Definitions volume of
215 IEEE Std 1003.1-2001, login names consist of characters in the portable
216 filename character set). The colon character was chosen as the replace‐
217 ment for the period character because it would never be allowed as a
218 character in a user name or group name on historical implementations.
219 The -R option is considered by some observers as an undesirable depar‐
221 ture from the historical UNIX system tools approach; since a tool,
222 find, already exists to recurse over directories, there seemed to be no
223 good reason to require other tools to have to duplicate that function‐
224 ality. However, the -R option was deemed an important user conve‐
225 nience, is far more efficient than forking a separate process for each
226 element of the directory hierarchy, and is in widespread historical
227 use.
228
230 None.
231
233 chmod, chgrp, the System Interfaces volume of IEEE Std 1003.1-2001,
234 chown()
235
237 Portions of this text are reprinted and reproduced in electronic form
238 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
239 -- Portable Operating System Interface (POSIX), The Open Group Base
240 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
241 Electrical and Electronics Engineers, Inc and The Open Group. In the
242 event of any discrepancy between this version and the original IEEE and
243 The Open Group Standard, the original IEEE and The Open Group Standard
244 is the referee document. The original Standard can be obtained online
245 at http://www.opengroup.org/unix/online.html .
246IEEE/The Open Group 2003 CHOWN(1P)