1CHOWN(P) POSIX Programmer's Manual CHOWN(P)
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6 chown - change the file ownership
7
9 chown [-hR] owner[:group] file ...
10 chown -R [-H | -L | -P ] owner[:group] file ...
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15 The chown utility shall set the user ID of the file named by each file
16 operand to the user ID specified by the owner operand.
17 For each file operand, or, if the -R option is used, each file encoun‐
19 tered while walking the directory trees specified by the file operands,
20 the chown utility shall perform actions equivalent to the chown() func‐
21 tion defined in the System Interfaces volume of IEEE Std 1003.1-2001,
22 called with the following arguments:
23 1. The file operand shall be used as the path argument.
25 2. The user ID indicated by the owner portion of the first operand
27 shall be used as the owner argument.
28 3. If the group portion of the first operand is given, the group ID
30 indicated by it shall be used as the group argument; otherwise, the
31 group ownership shall not be changed.
32 Unless chown is invoked by a process with appropriate privileges, the
34 set-user-ID and set-group-ID bits of a regular file shall be cleared
35 upon successful completion; the set-user-ID and set-group-ID bits of
36 other file types may be cleared.
37
39 The chown utility shall conform to the Base Definitions volume of
40 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
41 The following options shall be supported by the implementation:
43 -h If the system supports user IDs for symbolic links, for each
45 file operand that names a file of type symbolic link, chown
46 shall attempt to set the user ID of the symbolic link. If the
47 system supports group IDs for symbolic links, and a group ID was
48 specified, for each file operand that names a file of type sym‐
49 bolic link, chown shall attempt to set the group ID of the sym‐
50 bolic link. If the system does not support user or group IDs for
51 symbolic links, for each file operand that names a file of type
52 symbolic link, chown shall do nothing more with the current file
53 and shall go on to any remaining files.
54 -H If the -R option is specified and a symbolic link referencing a
56 file of type directory is specified on the command line, chown
57 shall change the user ID (and group ID, if specified) of the
58 directory referenced by the symbolic link and all files in the
59 file hierarchy below it.
60 -L If the -R option is specified and a symbolic link referencing a
62 file of type directory is specified on the command line or
63 encountered during the traversal of a file hierarchy, chown
64 shall change the user ID (and group ID, if specified) of the
65 directory referenced by the symbolic link and all files in the
66 file hierarchy below it.
67 -P If the -R option is specified and a symbolic link is specified
69 on the command line or encountered during the traversal of a
70 file hierarchy, chown shall change the owner ID (and group ID,
71 if specified) of the symbolic link if the system supports this
72 operation. The chown utility shall not follow the symbolic link
73 to any other part of the file hierarchy.
74 -R Recursively change file user and group IDs. For each file oper‐
76 and that names a directory, chown shall change the user ID (and
77 group ID, if specified) of the directory and all files in the
78 file hierarchy below it. Unless a -H, -L, or -P option is speci‐
79 fied, it is unspecified which of these options will be used as
80 the default.
81 Specifying more than one of the mutually-exclusive options -H, -L, and
84 -P shall not be considered an error. The last option specified shall
85 determine the behavior of the utility.
86
88 The following operands shall be supported:
89 owner[:group]
91 A user ID and optional group ID to be assigned to file. The
92 owner portion of this operand shall be a user name from the user
93 database or a numeric user ID. Either specifies a user ID which
94 shall be given to each file named by one of the file operands.
95 If a numeric owner operand exists in the user database as a user
96 name, the user ID number associated with that user name shall be
97 used as the user ID. Similarly, if the group portion of this op‐
98 erand is present, it shall be a group name from the group data‐
99 base or a numeric group ID. Either specifies a group ID which
100 shall be given to each file. If a numeric group operand exists
101 in the group database as a group name, the group ID number asso‐
102 ciated with that group name shall be used as the group ID.
103 file A pathname of a file whose user ID is to be modified.
105
108 Not used.
109
111 None.
112
114 The following environment variables shall affect the execution of
115 chown:
116 LANG Provide a default value for the internationalization variables
118 that are unset or null. (See the Base Definitions volume of
119 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
120 ables for the precedence of internationalization variables used
121 to determine the values of locale categories.)
122 LC_ALL If set to a non-empty string value, override the values of all
124 the other internationalization variables.
125 LC_CTYPE
127 Determine the locale for the interpretation of sequences of
128 bytes of text data as characters (for example, single-byte as
129 opposed to multi-byte characters in arguments).
130 LC_MESSAGES
132 Determine the locale that should be used to affect the format
133 and contents of diagnostic messages written to standard error.
134 NLSPATH
136 Determine the location of message catalogs for the processing of
137 LC_MESSAGES .
138
141 Default.
142
144 Not used.
145
147 The standard error shall be used only for diagnostic messages.
148
150 None.
151
153 None.
154
156 The following exit values shall be returned:
157 0 The utility executed successfully and all requested changes were
159 made.
160 >0 An error occurred.
162
165 Default.
166 The following sections are informative.
168
170 Only the owner of a file or the user with appropriate privileges may
171 change the owner or group of a file.
172 Some implementations restrict the use of chown to a user with appropri‐
174 ate privileges.
175
177 None.
178
180 The System V and BSD versions use different exit status codes. Some
181 implementations used the exit status as a count of the number of errors
182 that occurred; this practice is unworkable since it can overflow the
183 range of valid exit status values. These are masked by specifying only
184 0 and >0 as exit values.
185 The functionality of chown is described substantially through refer‐
187 ences to functions in the System Interfaces volume of
188 IEEE Std 1003.1-2001. In this way, there is no duplication of effort
189 required for describing the interactions of permissions, multiple
190 groups, and so on.
191 The 4.3 BSD method of specifying both owner and group was included in
193 this volume of IEEE Std 1003.1-2001 because:
194 * There are cases where the desired end condition could not be
196 achieved using the chgrp and chown (that only changed the user ID)
197 utilities. (If the current owner is not a member of the desired
198 group and the desired owner is not a member of the current group,
199 the chown() function could fail unless both owner and group are
200 changed at the same time.)
201 * Even if they could be changed independently, in cases where both are
203 being changed, there is a 100% performance penalty caused by being
204 forced to invoke both utilities.
205 The BSD syntax user[. group] was changed to user[: group] in this vol‐
207 ume of IEEE Std 1003.1-2001 because the period is a valid character in
208 login names (as specified by the Base Definitions volume of
209 IEEE Std 1003.1-2001, login names consist of characters in the portable
210 filename character set). The colon character was chosen as the replace‐
211 ment for the period character because it would never be allowed as a
212 character in a user name or group name on historical implementations.
213 The -R option is considered by some observers as an undesirable depar‐
215 ture from the historical UNIX system tools approach; since a tool,
216 find, already exists to recurse over directories, there seemed to be no
217 good reason to require other tools to have to duplicate that function‐
218 ality. However, the -R option was deemed an important user conve‐
219 nience, is far more efficient than forking a separate process for each
220 element of the directory hierarchy, and is in widespread historical
221 use.
222
224 None.
225
227 chmod , chgrp , the System Interfaces volume of IEEE Std 1003.1-2001,
228 chown()
229
231 Portions of this text are reprinted and reproduced in electronic form
232 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
233 -- Portable Operating System Interface (POSIX), The Open Group Base
234 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
235 Electrical and Electronics Engineers, Inc and The Open Group. In the
236 event of any discrepancy between this version and the original IEEE and
237 The Open Group Standard, the original IEEE and The Open Group Standard
238 is the referee document. The original Standard can be obtained online
239 at http://www.opengroup.org/unix/online.html .
240IEEE/The Open Group 2003 CHOWN(P)