usermod

Add the user to the supplementary group(s). Use only with the -G option.

Allow names that do not conform to standards.

update the comment field of the user in /etc/passwd, which is normally modified using the chfn(1) utility.

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. If the current home directory does not exist the new home directory will not be created.

The date on which the user account will be disabled. The date is specified in the format YYYY-MM-DD. Integers as input are interpreted as days after 1970-01-01. An input of -1 or an empty string will blank the account expiration field in the shadow password file. The account will remain available with no date limit. This option requires a /etc/shadow file. A /etc/shadow entry will be created if there were none.

defines the number of days after the password exceeded its maximum age during which the user may still login by immediately replacing the password. This grace period before the account becomes inactive is stored in the shadow password file. An input of 0 will disable an expired password with no delay. An input of -1 will blank the respective field in the shadow password file. See shadow(5) for more information. This option requires a /etc/shadow file. A /etc/shadow entry will be created if there were none.

The name or numerical ID of the user's new primary group. The group must exist. Any file from the user's home directory owned by the previous primary group of the user will be owned by this new group. The group ownership of files outside of the user's home directory must be fixed manually. The change of the group ownership of files inside of the user's home directory is also not done if the home dir owner uid is different from the current or new user id. This is a safety measure for special home directories such as /.

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 must exist. 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 the -a option, which appends the user to the current supplementary group list.

The name of the user will be changed from LOGIN to NEW_LOGIN. Nothing else is changed. In particular, the user's home directory or mail spool should probably be renamed manually to reflect the new login name.

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. Note: if you wish to lock the account (not only access with a password), you should also set the EXPIRE_DATE to 1.

moves the content of the user's home directory to the new location. If the current home directory does not exist the new home directory will not be created. This option is only valid in combination with the -d (or --home) option. usermod will try to adapt the ownership of the files and to copy the modes, ACL and extended attributes, but manual changes might be needed afterwards.

allows to change the user ID to a non-unique value. This option is only valid in combination with the -u option. As a user identity serves as key to map between users on one hand and permissions, file ownerships and other aspects that determine the system's behavior on the other hand, more than one login name will access the account of the given UID.

defines a new password for the user. PASSWORD is expected to be encrypted, as returned by crypt (3). Note: Avoid this option on the command line because the password (or encrypted password) will be visible by users listing the processes. The password will be written in the local /etc/passwd or /etc/shadow file. This might differ from the password database configured in your PAM configuration. You should make sure the password respects the system's password policy.

Remove the user from named supplementary group(s). Use only with the -G option.

Apply changes in the CHROOT_DIR directory and use the configuration files from the CHROOT_DIR directory. Only absolute paths are supported.

Apply changes within the directory tree starting with PREFIX_DIR and use as well the configuration files located there. This option does not chroot and is intended for preparing a cross-compilation target. Some limitations: NIS and LDAP users/groups are not verified. PAM authentication is using the host files. No SELINUX support.

changes the user's login shell. An empty string for SHELL blanks the field in /etc/passwd and logs the user into the system's default shell.

The new value of the user's ID. This value must be unique, unless the -o option is used. The value must be non-negative. The user's mailbox, and any files which the user owns and which are located in the user's home directory will have the file user ID changed automatically. The ownership of files outside of the user's home directory must be fixed manually. The change of the user ownership of files inside of the user's home directory is also not done if the home dir owner uid is different from the current or new user id. This is a safety measure for special home directories such as /. No check

Unlock a user's password. This removes the '!' in front of the encrypted password. You can't use this option with -p or -L. Note: if you wish to unlock the account (not only access with a password), you should also set the EXPIRE_DATE (for example to 99999, or to the EXPIRE value from /etc/default/useradd).

Add a range of subordinate uids to the user's account. This option may be specified multiple times to add multiple ranges to a user's account. No checks will be performed with regard to SUB_UID_MIN, SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.

Remove a range of subordinate uids from the user's account. This option may be specified multiple times to remove multiple ranges to a user's account. When both --del-subuids and --add-subuids are specified, the removal of all subordinate uid ranges happens before any subordinate uid range is added. No checks will be performed with regard to SUB_UID_MIN, SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.

Add a range of subordinate gids to the user's account. This option may be specified multiple times to add multiple ranges to a user's account. No checks will be performed with regard to SUB_GID_MIN, SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.

Remove a range of subordinate gids from the user's account. This option may be specified multiple times to remove multiple ranges to a user's account. When both --del-subgids and --add-subgids are specified, the removal of all subordinate gid ranges happens before any subordinate gid range is added. No checks will be performed with regard to SUB_GID_MIN, SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.

defines the SELinux user to be mapped with LOGIN. An empty string ("") will remove the respective entry (if any). Note that the shadow system doesn't store the selinux-user, it uses semanage(8) for that.

defines the SELinux MLS range for the new account. Note that the shadow system doesn't store the selinux-range, it uses semanage(8) for that. This option is only valid if the -Z (or --selinux-user) option is specified.