usermod(8) usermod(8)

usermod – modify a user account

usermod [-D binddn] [-P path] [-g gid [-o]] [-p password]
[–service service] [–help] [–usage] [-v] account

usermod modifies an user account using the values specified on the com-
mand line.

-c, –comment comment
This option specifies the new users finger information. It is
normally modified using the chfn(1) utility.

-d, –home homedir
This option specifies the new home directory of the user.

-e, –expire expire
With this option the date when the account will be expired can
be changed. expiredate has to be specified as number of days
since January 1st, 1970. The date may also be expressed in the
format YYYY-MM-DD.

-f, –inactive inactive
This option is used to set the number of days of inactivity
after a password has expired before the account is locked. A
user whose account is locked must contact the system adminis-
trator before being able to use the account again. A value of
-1 disables this feature.

-G, –groups group,…
With this option a list of supplementary groups can be speci-
fied, which the user should become a member of. Each group is
separated from the next one only by a comma, without whitespace.
The user is removed from all other groups not specified.

-g, –gid gid
The group name or number of the user’s new primary group. The
group name must exist and a group number must refer to an
already existing group.

-l, –login name
Specify the new account name for the user. The account name must
begin with an alphabetic character and the rest of the string
should be from the POSIX portable character class. Nothing else
is changed.

-m, –move_home
Move the user’s home directory to the new directory specified
with the -d option. If the old directory does not exist, nothing
is done. If the new directory already exists, the program aborts
with an error.

-o, –non-unique
Allow duplicate (non-unique) User IDs.

-p, –password password
Encrypted password as returned by crypt(3) as the new password.

-s, –shell shell
Specify user’s new login shell. The value of shell must be a
valid executable file. It is normally modified using the chsh(1)

-u, –uid uid
Change the userid to be the given number. This value must be
positive and unique (unless the -o option is used). Any file
with the old UID of the user and which is located in the direc-
tory tree rooted at the user’s home directory will be changed to
be owned by the new UID automatically.

-D, –binddn binddn
Use the Distinguished Name binddn to bind to the LDAP directory.
The user will be prompted for a password for simple authentica-

-L, –lock
A system administrator can lock the account of the specified

-U, –unlock
A system administrator can unlock the specified account, if the
account is not passwordless afterwards (it will not unlock an
account that has only “!” as a password).

-P, –path path
The passwd and shadow files are located below the specified
directory path. usermod will use this files, not /etc/passwd
and /etc/shadow.

–service service
Modify the account from a special directory. The default is
files, but ldap is also valid.

–help Print a list of valid options with a short description.

Print a short list of valid options.

-v, –version
Print the version number and exit.

usermod will not allow you to change the name, User ID or home direc-
tory of a user, which is logged in. usermod will not change the User ID
of running processes and not the ownership of crontab and at jobs.

/etc/group – group information
/etc/passwd – user account information
/etc/shadow – shadow user account information

passwd(1), login.defs(5), group(5), passwd(5), shadow(5), useradd(8),

Thorsten Kukuk <>

pwdutils May 2006 usermod(8)

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