1USERMOD(8) System Management Commands USERMOD(8)
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6 usermod - modify a user account
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9 usermod [options] LOGIN
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12 The usermod command modifies the system account files to reflect the
13 changes that are specified on the command line.
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16 The options which apply to the usermod command are:
17 -a, --append
19 Add the user to the supplementary group(s). Use only with the -G
20 option.
21 -c, --comment COMMENT
23 The new value of the user's password file comment field. It is
24 normally modified using the chfn(1) utility.
25 -d, --home HOME_DIR
27 The user's new login directory.
28 If the -m option is given, the contents of the current home
30 directory will be moved to the new home directory, which is created
31 if it does not already exist. If the current home directory does
32 not exist the new home directory will not be created.
33 -e, --expiredate EXPIRE_DATE
35 The date on which the user account will be disabled. The date is
36 specified in the format YYYY-MM-DD.
37 An empty EXPIRE_DATE argument will disable the expiration of the
39 account.
40 This option requires a /etc/shadow file. A /etc/shadow entry will
42 be created if there were none.
43 -f, --inactive INACTIVE
45 The number of days after a password expires until the account is
46 permanently disabled.
47 A value of 0 disables the account as soon as the password has
49 expired, and a value of -1 disables the feature.
50 This option requires a /etc/shadow file. A /etc/shadow entry will
52 be created if there were none.
53 -g, --gid GROUP
55 The group name or number of the user's new initial login group. The
56 group must exist.
57 Any file from the user's home directory owned by the previous
59 primary group of the user will be owned by this new group.
60 The group ownership of files outside of the user's home directory
62 must be fixed manually.
63 The change of the group ownership of files inside of the user's
65 home directory is also not done if the home dir owner uid is
66 different from the current or new user id. This is safety measure
67 for special home directories such as /.
68 -G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
70 A list of supplementary groups which the user is also a member of.
71 Each group is separated from the next by a comma, with no
72 intervening whitespace. The groups are subject to the same
73 restrictions as the group given with the -g option.
74 If the user is currently a member of a group which is not listed,
76 the user will be removed from the group. This behaviour can be
77 changed via the -a option, which appends the user to the current
78 supplementary group list.
79 -l, --login NEW_LOGIN
81 The name of the user will be changed from LOGIN to NEW_LOGIN.
82 Nothing else is changed. In particular, the user's home directory
83 or mail spool should probably be renamed manually to reflect the
84 new login name.
85 -L, --lock
87 Lock a user's password. This puts a '!' in front of the encrypted
88 password, effectively disabling the password. You can't use this
89 option with -p or -U.
90 Note: if you wish to lock the account (not only access with a
92 password), you should also set the EXPIRE_DATE to 1.
93 -m, --move-home
95 Move the content of the user's home directory to the new location.
96 If the current home directory does not exist the new home directory
97 will not be created.
98 This option is only valid in combination with the -d (or --home)
100 option.
101 usermod will try to adapt the ownership of the files and to copy
103 the modes, ACL and extended attributes, but manual changes might be
104 needed afterwards.
105 -o, --non-unique
107 When used with the -u option, this option allows to change the user
108 ID to a non-unique value.
109 -p, --password PASSWORD
111 The encrypted password, as returned by crypt(3).
112 Note: This option is not recommended because the password (or
114 encrypted password) will be visible by users listing the processes.
115 You should make sure the password respects the system's password
117 policy.
118 -R, --root CHROOT_DIR
120 Apply changes in the CHROOT_DIR directory and use the configuration
121 files from the CHROOT_DIR directory.
122 -s, --shell SHELL
124 The name of the user's new login shell. Setting this field to blank
125 causes the system to select the default login shell.
126 -u, --uid UID
128 The new numerical value of the user's ID.
129 This value must be unique, unless the -o option is used. The value
131 must be non-negative.
132 The user's mailbox, and any files which the user owns and which are
134 located in the user's home directory will have the file user ID
135 changed automatically.
136 The ownership of files outside of the user's home directory must be
138 fixed manually.
139 The change of the user ownership of files inside of the user's home
141 directory is also not done if the home dir owner uid is different
142 from the current or new user id. This is safety measure for special
143 home directories such as /.
144 No checks will be performed with regard to the UID_MIN, UID_MAX,
146 SYS_UID_MIN, or SYS_UID_MAX from /etc/login.defs.
147 -U, --unlock
149 Unlock a user's password. This removes the '!' in front of the
150 encrypted password. You can't use this option with -p or -L.
151 Note: if you wish to unlock the account (not only access with a
153 password), you should also set the EXPIRE_DATE (for example to
154 99999, or to the EXPIRE value from /etc/default/useradd).
155 -Z, --selinux-user SEUSER
157 The new SELinux user for the user's login.
158 A blank SEUSER will remove the SELinux user mapping for user LOGIN
160 (if any).
161
163 You must make certain that the named user is not executing any
164 processes when this command is being executed if the user's numerical
165 user ID, the user's name, or the user's home directory is being
166 changed. usermod checks this on Linux, but only check if the user is
167 logged in according to utmp on other architectures.
168 You must change the owner of any crontab files or at jobs manually.
170 You must make any changes involving NIS on the NIS server.
172
174 The following configuration variables in /etc/login.defs change the
175 behavior of this tool:
176 MAIL_DIR (string)
178 The mail spool directory. This is needed to manipulate the mailbox
179 when its corresponding user account is modified or deleted. If not
180 specified, a compile-time default is used.
181 MAIL_FILE (string)
183 Defines the location of the users mail spool files relatively to
184 their home directory.
185 The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod, and
187 userdel to create, move, or delete the user's mail spool.
188 If MAIL_CHECK_ENAB is set to yes, they are also used to define the MAIL
190 environment variable.
191 MAX_MEMBERS_PER_GROUP (number)
193 Maximum members per group entry. When the maximum is reached, a new
194 group entry (line) is started in /etc/group (with the same name,
195 same password, and same GID).
196 The default value is 0, meaning that there are no limits in the
198 number of members in a group.
199 This feature (split group) permits to limit the length of lines in
201 the group file. This is useful to make sure that lines for NIS
202 groups are not larger than 1024 characters.
203 If you need to enforce such limit, you can use 25.
205 Note: split groups may not be supported by all tools (even in the
207 Shadow toolsuite). You should not use this variable unless you
208 really need it.
209
211 /etc/group
212 Group account information.
213 /etc/gshadow
215 Secure group account information.
216 /etc/login.defs
218 Shadow password suite configuration.
219 /etc/passwd
221 User account information.
222 /etc/shadow
224 Secure user account information.
225
227 chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
228 groupdel(8), groupmod(8), login.defs(5), useradd(8), userdel(8).
229shadow-utils 4.1.5.1 03/14/2019 USERMOD(8)