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.
chgrp — change the file group ownership
chgrp [−h] group file...
chgrp −R [−H|−L|−P] group file...
The chgrp utility shall set the group ID of the file named by each file operand to the group ID specified by the group 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 chgrp utility shall perform actions equivalent to the chown() function defined in the System Interfaces volume of POSIX.1‐2008, called with the following arguments:
- The file operand shall be used as the path argument.
- The user ID of the file shall be used as the owner argument.
Unless 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.
The chgrp 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:
- The specified group ID shall be used as the group argument.
- For each file operand that names a file of type symbolic link, chgrp shall attempt to set the group ID of the symbolic link instead of the file referenced by the symbolic link.
- If the −R option is specified and a symbolic link referencing a file of type directory is specified on the command line, chgrp shall change the group of the directory referenced by the symbolic link and all files in the file hierarchy below it.
- 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, chgrp shall change the group of the directory referenced by the symbolic link and all files in the file hierarchy below it.
- 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, chgrp shall change the group ID of the symbolic link. The chgrp utility shall not follow the symbolic link to any other part of the file hierarchy.
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:
- Recursively change file group IDs. For each file operand that names a directory, chgrp shall change the group 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.
- 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 file operands. If a numeric 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.
The following environment variables shall affect the execution of chgrp:
- A pathname of a file whose group ID is to be modified.
- 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.)
- If set to a non-empty string value, override the values of all the other internationalization variables.
- 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).
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
The standard error shall be used only for diagnostic messages.
The following exit values shall be returned:
- Determine the location of message catalogs for the processing of LC_MESSAGES.
- The utility executed successfully and all requested changes were made.
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 chgrp to a user with appropriate privileges when the group specified is not the effective group ID or one of the supplementary group IDs of the calling process.
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.
The functionality of chgrp is described substantially through references to chown(). In this way, there is no duplication of effort required for describing the interactions of permissions, multiple groups, and so on.
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()
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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