Computer Science
USERMOD(8) USERMOD(8)
NAME
usermod - Modify a user account
SYNOPSIS
usermod [-c comment] [-d home_dir [ -m]]
[-e expire_date] [-f inactive_time]
[-g initial_group] [-G group[,...]]
[-l login_name] [-s shell]
[-u uid [ -o]] [-L|-U] login
DESCRIPTION
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
-c comment
The new value of the user's password file comment
field. It is normally modified using the chfn(1)
utility.
-d home_dir
The user's 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 expire_date
The date on which the user account will be dis-
abled. The date is specified in the format
MM/DD/YY.
-f inactive_days
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 initial_group
The group name or number of the user's 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 group,[...]
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
-l login_name
The name of the user will be changed from login to
login_name. Nothing else is changed. In particu-
lar, the user's home directory name should probably
be changed to reflect the new login name.
-s shell
The name of the user's new login shell. Setting
this field to blank causes the system to select the
default login shell.
-u uid The numerical value of the user's ID. This value
must be unique, unless the -o option is used. The
value must be non-negative. Values between 0 and
99 are typically reserved for system accounts. Any
files which the user owns and which are located in
the directory tree rooted at the user's home direc-
tory will have the file user ID changed automati-
cally. Files outside of the user's home directory
must be altered manually.
-L Lock a user's password. This puts a '!' in front
of the encrypted password, effectively disabling
the password. You can't use this option with -p or
-U.
-U Unlock a user's password. This removes the '!' in
front of the encrypted password. You can't use
this option with -p or -L.
CAVEATS
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 user's 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 manu-
ally. You must make any changes involving NIS on the NIS
server.
FILES
/etc/passwd - user account information
/etc/shadow - secure user account information
/etc/group - group information
SEE ALSO
chfn(1), chsh(1), groupadd(8), groupdel(8), groupmod(8),
passwd(1), useradd(8), userdel(8)
AUTHOR
Julianne Frances Haugh (jfh@tab.com)
1
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