USERMOD(8) System Management Commands USERMOD(8)
usermod - modify a user account
usermod [options] LOGIN
The usermod command modifies the system account files to reflect the
changes that are specified on the command line.
The options which apply to the usermod command are:
Add the user to the supplemental group(s). Use only with -G option.
-c, --comment COMMENT
The new value of the users password file comment field. It is
normally modified using the chfn(1) utility.
-d, --home HOME_DIR
The users new login directory. If the -m option is given the
contents of the current home directory will be moved to the new home
directory, which is created if it does not already exist.
-e, --expiredate EXPIRE_DATE
The date on which the user account will be disabled. The date is
specified in the format YYYY-MM-DD.
-f, --inactive INACTIVE
The number of days after a password expires until the account is
permanently disabled. A value of 0 disables the account as soon as
the password has expired, and a value of -1 disables the feature.
The default value is -1.
-g, --gid GROUP
The group name or number of the users new initial login group. The
group name must exist. A group number must refer to an already
existing group. The default group number is 1.
-G, --groups GROUP1[,GROUP2,...[,GROUPN]]]
A list of supplementary groups which the user is also a member of.
Each group is separated from the next by a comma, with no
intervening whitespace. The groups are subject to the same
restrictions as the group given with the -g option. If the user is
currently a member of a group which is not listed, the user will be
removed from the group. This behaviour can be changed via -a option,
which appends user to the current supplementary group list.
-l, --login NEW_LOGIN
The name of the user will be changed from LOGIN to NEW_LOGIN.
Nothing else is changed. In particular, the users home directory
name should probably be changed to reflect the new login name.
Lock a users password. This puts a ! in front of the encrypted
password, effectively disabling the password. You cant use this
option with -p or -U.
When used with the -u option, this option allows to change the user
ID to a non-unique value.
-p, --password PASSWORD
The encrypted password, as returned by crypt(3).
-s, --shell SHELL
The name of the users new login shell. Setting this field to blank
causes the system to select the default login shell.
-u, --uid UID
The numerical value of the users ID. This value must be unique,
unless the -o option is used. The value must be non-negative. Values
between 0 and 999 are typically reserved for system accounts. Any
files which the user owns and which are located in the directory
tree rooted at the users home directory will have the file user ID
changed automatically. Files outside of the users home directory
must be altered manually.
Unlock a users password. This removes the ! in front of the
encrypted password. You cant use this option with -p or -L.
usermod will not allow you to change the name of a user who is logged
in. You must make certain that the named user is not executing any
processes when this command is being executed if the users numerical
user ID is being changed. You must change the owner of any crontab
files manually. You must change the owner of any at jobs manually. You
must make any changes involving NIS on the NIS server.
Group account information.
User account information.
Secure user account information.
chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
groupdel(8), groupmod(8), login.defs(5), useradd(8), userdel(8).
System Management Commands 02/25/2007 USERMOD(8)