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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
CHOWN(1P) POSIX Programmer's Manual CHOWN(1P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
chown — change the file ownership
chown [−h] owner[:group] file...
chown −R [−H|−L|−P] owner[:group] file...
The chown utility shall set the user ID of the file named by each
file operand to the user ID specified by the owner operand.
For each file operand, or, if the −R option is used, each file
encountered while walking the directory trees specified by the file
operands, the chown utility shall perform actions equivalent to the
chown() function defined in the System Interfaces volume of
POSIX.1‐2008, called with the following arguments:
1. The file operand shall be used as the path argument.
2. The user ID indicated by the owner portion of the first operand
shall be used as the owner argument.
3. If the group portion of the first operand is given, the group ID
indicated by it shall be used as the group argument; otherwise,
the group ownership shall not be changed.
Unless chown is invoked by a process with appropriate privileges, the
set-user-ID and set-group-ID bits of a regular file shall be cleared
upon successful completion; the set-user-ID and set-group-ID bits of
other file types may be cleared.
The chown utility shall conform to the Base Definitions volume of
POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported by the implementation:
−h For each file operand that names a file of type symbolic
link, chown shall attempt to set the user ID of the
symbolic link. If a group ID was specified, for each file
operand that names a file of type symbolic link, chown
shall attempt to set the group ID of the symbolic link.
−H If the −R option is specified and a symbolic link
referencing a file of type directory is specified on the
command line, chown shall change the user ID (and group ID,
if specified) of the directory referenced by the symbolic
link and all files in the file hierarchy below it.
−L If the −R option is specified and a symbolic link
referencing a file of type directory is specified on the
command line or encountered during the traversal of a file
hierarchy, chown shall change the user ID (and group ID, if
specified) of the directory referenced by the symbolic link
and all files in the file hierarchy below it.
−P If the −R option is specified and a symbolic link is
specified on the command line or encountered during the
traversal of a file hierarchy, chown shall change the owner
ID (and group ID, if specified) of the symbolic link. The
chown utility shall not follow the symbolic link to any
other part of the file hierarchy.
−R Recursively change file user and group IDs. For each file
operand that names a directory, chown shall change the user
ID (and group ID, if specified) of the directory and all
files in the file hierarchy below it. Unless a −H, −L, or
−P option is specified, it is unspecified which of these
options will be used as the default.
Specifying more than one of the mutually-exclusive options −H, −L,
and −P shall not be considered an error. The last option specified
shall determine the behavior of the utility.
The following operands shall be supported:
owner[:group]
A user ID and optional group ID to be assigned to file.
The owner portion of this operand shall be a user name from
the user database or a numeric user ID. Either specifies a
user ID which shall be given to each file named by one of
the file operands. If a numeric owner operand exists in the
user database as a user name, the user ID number associated
with that user name shall be used as the user ID.
Similarly, if the group portion of this operand is present,
it shall be a group name from the group database or a
numeric group ID. Either specifies a group ID which shall
be given to each file. If a numeric group operand exists in
the group database as a group name, the group ID number
associated with that group name shall be used as the group
ID.
file A pathname of a file whose user ID is to be modified.
Not used.
None.
The following environment variables shall affect the execution of
chown:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions
volume of POSIX.1‐2008, Section 8.2, Internationalization
Variables for the precedence of internationalization
variables used to determine the values of locale
categories.)
LC_ALL If set to a non-empty string value, override the values of
all the other internationalization variables.
LC_CTYPE Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte
as opposed to multi-byte characters in arguments).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Default.
Not used.
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be returned:
0 The utility executed successfully and all requested changes
were made.
>0 An error occurred.
Default.
The following sections are informative.
Only the owner of a file or the user with appropriate privileges may
change the owner or group of a file.
Some implementations restrict the use of chown to a user with
appropriate privileges.
None.
The System V and BSD versions use different exit status codes. Some
implementations used the exit status as a count of the number of
errors that occurred; this practice is unworkable since it can
overflow the range of valid exit status values. These are masked by
specifying only 0 and >0 as exit values.
The functionality of chown is described substantially through
references to functions in the System Interfaces volume of
POSIX.1‐2008. In this way, there is no duplication of effort required
for describing the interactions of permissions, multiple groups, and
so on.
The 4.3 BSD method of specifying both owner and group was included in
this volume of POSIX.1‐2008 because:
* There are cases where the desired end condition could not be
achieved using the chgrp and chown (that only changed the user
ID) utilities. (If the current owner is not a member of the
desired group and the desired owner is not a member of the
current group, the chown() function could fail unless both owner
and group are changed at the same time.)
* Even if they could be changed independently, in cases where both
are being changed, there is a 100% performance penalty caused by
being forced to invoke both utilities.
The BSD syntax user[.group] was changed to user[:group] in this
volume of POSIX.1‐2008 because the <period> is a valid character in
login names (as specified by the Base Definitions volume of
POSIX.1‐2008, login names consist of characters in the portable
filename character set). The <colon> character was chosen as the
replacement for the <period> character because it would never be
allowed as a character in a user name or group name on historical
implementations.
The −R option is considered by some observers as an undesirable
departure from the historical UNIX system tools approach; since a
tool, find, already exists to recurse over directories, there seemed
to be no good reason to require other tools to have to duplicate that
functionality. However, the −R option was deemed an important user
convenience, is far more efficient than forking a separate process
for each element of the directory hierarchy, and is in widespread
historical use.
None.
chgrp(1p), chmod(1p)
The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
Variables, Section 12.2, Utility Syntax Guidelines
The System Interfaces volume of POSIX.1‐2008, chown(3p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 CHOWN(1P)
Pages that refer to this page: chgrp(1p)