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usermod

Article Index
1. Name
2. Synopsis
3. Frequently used options
4. Examples

1. Name

usermod [man page] - modify a user account

2. Synopsis

usermod [options] LOGIN

3. Frequently used options

-e, --expiredate EXPIRE_DATE
      The date on which the user account will be disabled. The date is
      specified in the format YYYY-MM-DD.
-L, --lock
      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
      Unlock a user’s password. This removes the ’!’ in front of the
      encrypted password. You can’t use this option with -p or -L.

4. Examples

Lets see how we can lock account for user linuxconfig. This will add "!" into /etc/shadow for user linuxconfig. NOTE: this command requires superusers privileges.

# usermod -L linuxcofnig

usermod - lock user account
Now we can try login with user linuxconfig and see if that works:

usermod - login test
With a -U option we can unlock account:

# usermod -U linuxcofnig

Check if the "!" is removed from etc/shadow:

# grep linuxconfig etc/shadow | head -c 15 |  sed -e 's/$/\n/'

To make account expire we can use --expiredate option. This will expire user account on 1 January 2010.

# usermod --expiredate 2010-01-01 linuxconfig