1GROUPMOD(8) System Management Commands GROUPMOD(8)
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6 groupmod - modify a group definition on the system
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9 groupmod [options] GROUP
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12 The groupmod command modifies the definition of the specified GROUP by
13 modifying the appropriate entry in the group database.
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16 The options which apply to the groupmod command are:
17 -a, --append GID
19 If group members are specified with -U, append them to the existing
20 member list, rather than replacing it.
21 -g, --gid GID
23 The group ID of the given GROUP will be changed to GID.
24 The value of GID must be a non-negative decimal integer. This value
26 must be unique, unless the -o option is used.
27 Users who use the group as primary group will be updated to keep
29 the group as their primary group.
30 Any files that have the old group ID and must continue to belong to
32 GROUP, must have their group ID changed manually.
33 No checks will be performed with regard to the GID_MIN, GID_MAX,
35 SYS_GID_MIN, or SYS_GID_MAX from /etc/login.defs.
36 -h, --help
38 Display help message and exit.
39 -n, --new-name NEW_GROUP
41 The name of the group will be changed from GROUP to NEW_GROUP name.
42 -o, --non-unique
44 When used with the -g option, allow to change the group GID to a
45 non-unique value.
46 -p, --password PASSWORD
48 The encrypted password, as returned by crypt(3).
49 Note: This option is not recommended because the password (or
51 encrypted password) will be visible by users listing the processes.
52 You should make sure the password respects the system's password
54 policy.
55 -R, --root CHROOT_DIR
57 Apply changes in the CHROOT_DIR directory and use the configuration
58 files from the CHROOT_DIR directory.
59 -P, --prefix PREFIX_DIR
61 Apply changes in the PREFIX_DIR directory and use the configuration
62 files from the PREFIX_DIR directory. This option does not chroot
63 and is intended for preparing a cross-compilation target. Some
64 limitations: NIS and LDAP users/groups are not verified. PAM
65 authentication is using the host files. No SELINUX support.
66 -U, --users
68 A list of usernames to add as members of the group.
69 The default behavior (if the -g, -N, and -U options are not
71 specified) is defined by the USERGROUPS_ENAB variable in
72 /etc/login.defs.
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75 The following configuration variables in /etc/login.defs change the
76 behavior of this tool:
77 MAX_MEMBERS_PER_GROUP (number)
79 Maximum members per group entry. When the maximum is reached, a new
80 group entry (line) is started in /etc/group (with the same name,
81 same password, and same GID).
82 The default value is 0, meaning that there are no limits in the
84 number of members in a group.
85 This feature (split group) permits to limit the length of lines in
87 the group file. This is useful to make sure that lines for NIS
88 groups are not larger than 1024 characters.
89 If you need to enforce such limit, you can use 25.
91 Note: split groups may not be supported by all tools (even in the
93 Shadow toolsuite). You should not use this variable unless you
94 really need it.
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97 /etc/group
98 Group account information.
99 /etc/gshadow
101 Secure group account information.
102 /etc/login.defs
104 Shadow password suite configuration.
105 /etc/passwd
107 User account information.
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110 The groupmod command exits with the following values:
111 0
113 E_SUCCESS: success
114 2
116 E_USAGE: invalid command syntax
117 3
119 E_BAD_ARG: invalid argument to option
120 4
122 E_GID_IN_USE: group id already in use
123 6
125 E_NOTFOUND: specified group doesn't exist
126 9
128 E_NAME_IN_USE: group name already in use
129 10
131 E_GRP_UPDATE: can't update group file
132 11
134 E_CLEANUP_SERVICE: can't setup cleanup service
135 12
137 E_PAM_USERNAME: can't determine your username for use with pam
138 13
140 E_PAM_ERROR: pam returned an error, see syslog facility id groupmod
141 for the PAM error message
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144 chfn(1), chsh(1), passwd(1), gpasswd(8), groupadd(8), groupdel(8),
145 login.defs(5), useradd(8), userdel(8), usermod(8).
146shadow-utils 4.9 11/19/2021 GROUPMOD(8)