# phpman > man > groupmod(8)

[GROUPMOD(8)](https://www.chedong.com/phpMan.php/man/GROUPMOD/8/markdown)                          System Management Commands                          [GROUPMOD(8)](https://www.chedong.com/phpMan.php/man/GROUPMOD/8/markdown)



## NAME
       groupmod - modify a group definition on the system

## SYNOPSIS
       **groupmod** [_options_] _GROUP_

## DESCRIPTION
       The **groupmod** command modifies the definition of the specified _GROUP_ by modifying the
       appropriate entry in the group database.

## OPTIONS
       The options which apply to the **groupmod** command are:

### -g --gid
           The group ID of the given _GROUP_ will be changed to _GID_.

           The value of _GID_ must be a non-negative decimal integer. This value must be unique,
           unless the **-o** option is used.

           Users who use the group as primary group will be updated to keep the group as their
           primary group.

           Any files that have the old group ID and must continue to belong to _GROUP_, must have
           their group ID changed manually.

           No checks will be performed with regard to the **GID**___**MIN**, **GID**___**MAX**, **SYS**___**GID**___**MIN**, or
           **SYS**___**GID**___**MAX** from /etc/login.defs.

### -h --help
           Display help message and exit.

### -n --new-name
           The name of the group will be changed from _GROUP_ to _NEW_GROUP_ name.

### -o --non-unique
           When used with the **-g** option, allow to change the group _GID_ to a non-unique value.

### -p --password
           The encrypted password, as returned by [**crypt**(3)](https://www.chedong.com/phpMan.php/man/crypt/3/markdown).

           **Note:** This option is not recommended because the password (or encrypted password) will be
           visible by users listing the processes.

           You should make sure the password respects the system's password policy.

### -R --root
           Apply changes in the _CHROOT_DIR_ directory and use the configuration files from the
           _CHROOT_DIR_ directory.

### -P --prefix
           Apply changes in the _PREFIX_DIR_ directory and use the configuration files from the
           _PREFIX_DIR_ directory. This option does not chroot and is intended for preparing a
           cross-compilation target. Some limitations: NIS and LDAP users/groups are not verified.
           PAM authentication is using the host files. No SELINUX support.

## CONFIGURATION
       The following configuration variables in /etc/login.defs change the behavior of this tool:

### MAX___MEMBERS___PER___GROUP (number)
           Maximum members per group entry. When the maximum is reached, a new group entry (line) is
           started in /etc/group (with the same name, same password, and same GID).

           The default value is 0, meaning that there are no limits in the number of members in a
           group.

           This feature (split group) permits to limit the length of lines in the group file. This
           is useful to make sure that lines for NIS groups are not larger than 1024 characters.

           If you need to enforce such limit, you can use 25.

           Note: split groups may not be supported by all tools (even in the Shadow toolsuite). You
           should not use this variable unless you really need it.

## FILES
       /etc/group
           Group account information.

       /etc/gshadow
           Secure group account information.

       /etc/login.defs
           Shadow password suite configuration.

       /etc/passwd
           User account information.

## EXIT VALUES
       The **groupmod** command exits with the following values:

       _0_
           E_SUCCESS: success

       _2_
           E_USAGE: invalid command syntax

       _3_
           E_BAD_ARG: invalid argument to option

       _4_
           E_GID_IN_USE: specified group doesn't exist

       _6_
           E_NOTFOUND: specified group doesn't exist

       _9_
           E_NAME_IN_USE: group name already in use

       _10_
           E_GRP_UPDATE: can't update group file

       _11_
           E_CLEANUP_SERVICE: can't setup cleanup service

       _12_
           E_PAM_USERNAME: can't determine your username for use with pam

       _13_
           E_PAM_ERROR: pam returned an error, see syslog facility id groupmod for the PAM error
           message

## SEE ALSO
       [**chfn**(1)](https://www.chedong.com/phpMan.php/man/chfn/1/markdown), [**chsh**(1)](https://www.chedong.com/phpMan.php/man/chsh/1/markdown), [**passwd**(1)](https://www.chedong.com/phpMan.php/man/passwd/1/markdown), [**gpasswd**(8)](https://www.chedong.com/phpMan.php/man/gpasswd/8/markdown), [**groupadd**(8)](https://www.chedong.com/phpMan.php/man/groupadd/8/markdown), [**groupdel**(8)](https://www.chedong.com/phpMan.php/man/groupdel/8/markdown), [**login.defs**(5)](https://www.chedong.com/phpMan.php/man/login.defs/5/markdown), [**useradd**(8)](https://www.chedong.com/phpMan.php/man/useradd/8/markdown),
       [**userdel**(8)](https://www.chedong.com/phpMan.php/man/userdel/8/markdown), [**usermod**(8)](https://www.chedong.com/phpMan.php/man/usermod/8/markdown).



shadow-utils 4.8.1                           02/06/2024                                  [GROUPMOD(8)](https://www.chedong.com/phpMan.php/man/GROUPMOD/8/markdown)