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.TH CHGRP "1P" 2013 "IEEE/The Open Group" "POSIX Programmer's Manual"
.SH PROLOG
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.

.SH NAME
chgrp
\(em change the file group ownership
.SH SYNOPSIS
.LP
.nf
chgrp \fB[\fR\(mih\fB] \fIgroup file\fR...
.P
chgrp \(miR \fB[\fR\(miH|\(miL|\(miP\fB] \fIgroup file\fR...
.fi
.SH DESCRIPTION
The
.IR chgrp
utility shall set the group ID of the file named by each
.IR file
operand to the group ID specified by the
.IR group
operand.
.P
For each
.IR file
operand, or, if the
.BR \(miR
option is used, each file encountered while walking the directory
trees specified by the
.IR file
operands, the
.IR chgrp
utility shall perform actions equivalent to the
\fIchown\fR()
function defined in the System Interfaces volume of POSIX.1\(hy2008, called with the following arguments:
.IP " *" 4
The
.IR file
operand shall be used as the
.IR path
argument.
.IP " *" 4
The user ID of the file shall be used as the
.IR owner
argument.
.IP " *" 4
The specified group ID shall be used as the
.IR group
argument.
.P
Unless
.IR chgrp
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.
.SH OPTIONS
The
.IR chgrp
utility shall conform to the Base Definitions volume of POSIX.1\(hy2008,
.IR "Section 12.2" ", " "Utility Syntax Guidelines".
.P
The following options shall be supported by the implementation:
.IP "\fB\(mih\fP" 10
For each
.IR file
operand that names a file of type symbolic link,
.IR chgrp
shall attempt to set the group ID of the symbolic link instead of the
file referenced by the symbolic link.
.IP "\fB\(miH\fP" 10
If the
.BR \(miR
option is specified and a symbolic link referencing a file of type
directory is specified on the command line,
.IR chgrp
shall change the group of the directory referenced by the symbolic link
and all files in the file hierarchy below it.
.IP "\fB\(miL\fP" 10
If the
.BR \(miR
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,
.IR chgrp
shall change the group of the directory referenced by the symbolic link
and all files in the file hierarchy below it.
.IP "\fB\(miP\fP" 10
If the
.BR \(miR
option is specified and a symbolic link is specified on the command
line or encountered during the traversal of a file hierarchy,
.IR chgrp
shall change the group ID of the symbolic link. The
.IR chgrp
utility shall not follow the symbolic link to any other part of the
file hierarchy.
.IP "\fB\(miR\fP" 10
Recursively change file group IDs. For each
.IR file
operand that names a directory,
.IR chgrp
shall change the group of the directory and all files in the
file hierarchy below it. Unless a
.BR \(miH ,
.BR \(miL ,
or
.BR \(miP
option is specified, it is unspecified which of these options will be
used as the default.
.P
Specifying more than one of the mutually-exclusive options
.BR \(miH ,
.BR \(miL ,
and
.BR \(miP
shall not be considered an error. The last option specified shall
determine the behavior of the utility.
.SH OPERANDS
The following operands shall be supported:
.IP "\fIgroup\fR" 10
A group name from the group database or a numeric group ID. Either
specifies a group ID to be given to each file named by one of the
.IR file
operands. If a numeric
.IR group
operand exists in the group database as a group name, the group ID
number associated with that group name is used as the group ID.
.IP "\fIfile\fR" 10
A pathname of a file whose group ID is to be modified.
.SH STDIN
Not used.
.SH "INPUT FILES"
None.
.SH "ENVIRONMENT VARIABLES"
The following environment variables shall affect the execution of
.IR chgrp :
.IP "\fILANG\fP" 10
Provide a default value for the internationalization variables that are
unset or null. (See the Base Definitions volume of POSIX.1\(hy2008,
.IR "Section 8.2" ", " "Internationalization Variables"
for the precedence of internationalization variables used to determine
the values of locale categories.)
.IP "\fILC_ALL\fP" 10
If set to a non-empty string value, override the values of all the
other internationalization variables.
.IP "\fILC_CTYPE\fP" 10
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).
.IP "\fILC_MESSAGES\fP" 10
.br
Determine the locale that should be used to affect the format and
contents of diagnostic messages written to standard error.
.IP "\fINLSPATH\fP" 10
Determine the location of message catalogs for the processing of
.IR LC_MESSAGES .
.SH "ASYNCHRONOUS EVENTS"
Default.
.SH STDOUT
Not used.
.SH STDERR
The standard error shall be used only for diagnostic messages.
.SH "OUTPUT FILES"
None.
.SH "EXTENDED DESCRIPTION"
None.
.SH "EXIT STATUS"
The following exit values shall be returned:
.IP "\00" 6
The utility executed successfully and all requested changes were made.
.IP >0 6
An error occurred.
.SH "CONSEQUENCES OF ERRORS"
Default.
.LP
.IR "The following sections are informative."
.SH "APPLICATION USAGE"
Only the owner of a file or the user with appropriate privileges may
change the owner or group of a file.
.P
Some implementations restrict the use of
.IR chgrp
to a user with appropriate privileges when the
.IR group
specified is not the effective group ID or one of the supplementary
group IDs of the calling process.
.SH EXAMPLES
None.
.SH RATIONALE
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. The standard developers chose to
mask these by specifying only 0 and >0 as exit values.
.P
The functionality of
.IR chgrp
is described substantially through references to
\fIchown\fR().
In this way, there is no duplication of effort required for describing
the interactions of permissions, multiple groups, and so on.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIchmod\fR\^",
.IR "\fIchown\fR\^"
.P
The Base Definitions volume of POSIX.1\(hy2008,
.IR "Chapter 8" ", " "Environment Variables",
.IR "Section 12.2" ", " "Utility Syntax Guidelines"
.P
The System Interfaces volume of POSIX.1\(hy2008,
.IR "\fIchown\fR\^(\|)"
.SH COPYRIGHT
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 .

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