NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CAVEATS | CONFIGURATION | FILES | SEE ALSO | COLOPHON

USERMOD(8)               System Management Commands               USERMOD(8)

NAME         top

       usermod - modify a user account

SYNOPSIS         top

       usermod [options] LOGIN

DESCRIPTION         top

       The usermod command modifies the system account files to reflect the
       changes that are specified on the command line.

OPTIONS         top

       The options which apply to the usermod command are:

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

       -c, --comment COMMENT
           The new value of the user's password file comment field. It is
           normally modified using the chfn(1) utility.

       -d, --home 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, --expiredate EXPIRE_DATE
           The date on which the user account will be disabled. The date is
           specified in the format YYYY-MM-DD.

           An empty EXPIRE_DATE argument will disable the expiration of the
           account.

           This option requires a /etc/shadow file. A /etc/shadow entry will
           be created if there were none.

       -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.

           This option requires a /etc/shadow file. A /etc/shadow entry will
           be created if there were none.

       -g, --gid GROUP
           The group name or number of the user's new initial login 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.

       -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 the -a option, which appends the 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 user's home directory
           or mail spool should probably be renamed manually to reflect the
           new login name.

       -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.

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

       -m, --move-home
           Move the content of the user's home directory to the new
           location.

           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.

       -o, --non-unique
           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).

           Note: This option is not recommended 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.

       -R, --root CHROOT_DIR
           Apply changes in the CHROOT_DIR directory and use the
           configuration files from the CHROOT_DIR directory.

       -s, --shell 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 UID
           The new numerical 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.

           No checks will be performed with regard to the UID_MIN, UID_MAX,
           SYS_UID_MIN, or SYS_UID_MAX from /etc/login.defs.

       -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.

           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).

       -v, --add-sub-uids FIRST-LAST
           Add a range of subordinate uids to the user's account.

           This option may be specified multiple times to add multiple
           ranges to a users account.

           No checks will be performed with regard to SUB_UID_MIN,
           SUB_UID_MAX, or SUB_UID_COUNT from /etc/login.defs.

       -V, --del-sub-uids FIRST-LAST
           Remove a range of subordinate uids from the user's account.

           This option may be specified multiple times to remove multiple
           ranges to a users account. When both --del-sub-uids and
           --add-sub-uids 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.

       -w, --add-sub-gids FIRST-LAST
           Add a range of subordinate gids to the user's account.

           This option may be specified multiple times to add multiple
           ranges to a users account.

           No checks will be performed with regard to SUB_GID_MIN,
           SUB_GID_MAX, or SUB_GID_COUNT from /etc/login.defs.

       -W, --del-sub-gids FIRST-LAST
           Remove a range of subordinate gids from the user's account.

           This option may be specified multiple times to remove multiple
           ranges to a users account. When both --del-sub-gids and
           --add-sub-gids 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.

       -Z, --selinux-user SEUSER
           The new SELinux user for the user's login.

           A blank SEUSER will remove the SELinux user mapping for user
           LOGIN (if any).

CAVEATS         top

       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, the user's name, or the user's home directory is being
       changed.  usermod checks this on Linux, but only check if the user is
       logged in according to utmp on other architectures.

       You must change the owner of any crontab files or at jobs manually.

       You must make any changes involving NIS on the NIS server.

CONFIGURATION         top

       The following configuration variables in /etc/login.defs change the
       behavior of this tool:

       MAIL_DIR (string)
           The mail spool directory. This is needed to manipulate the
           mailbox when its corresponding user account is modified or
           deleted. If not specified, a compile-time default is used.

       MAIL_FILE (string)
           Defines the location of the users mail spool files relatively to
           their home directory.

       The MAIL_DIR and MAIL_FILE variables are used by useradd, usermod,
       and userdel to create, move, or delete the user's mail spool.

       MAX_MEMBERS_PER_GROUP (number)
           Maximum members per group entry. When the maximum is reached, a
           new group entry (line) is started in /etc/group (with the same
           name, same password, and same GID).

           The default value is 0, meaning that there are no limits in the
           number of members in a group.

           This feature (split group) permits to limit the length of lines
           in the group file. This is useful to make sure that lines for NIS
           groups are not larger than 1024 characters.

           If you need to enforce such limit, you can use 25.

           Note: split groups may not be supported by all tools (even in the
           Shadow toolsuite). You should not use this variable unless you
           really need it.

       SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number)
           If /etc/subuid exists, the commands useradd and newusers (unless
           the user already have subordinate group IDs) allocate
           SUB_GID_COUNT unused group IDs from the range SUB_GID_MIN to
           SUB_GID_MAX for each new user.

           The default values for SUB_GID_MIN, SUB_GID_MAX, SUB_GID_COUNT
           are respectively 100000, 600100000 and 10000.

       SUB_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number)
           If /etc/subuid exists, the commands useradd and newusers (unless
           the user already have subordinate user IDs) allocate
           SUB_UID_COUNT unused user IDs from the range SUB_UID_MIN to
           SUB_UID_MAX for each new user.

           The default values for SUB_UID_MIN, SUB_UID_MAX, SUB_UID_COUNT
           are respectively 100000, 600100000 and 10000.

FILES         top

       /etc/group
           Group account information.

       /etc/gshadow
           Secure group account information.

       /etc/login.defs
           Shadow password suite configuration.

       /etc/passwd
           User account information.

       /etc/shadow
           Secure user account information.

       /etc/subgid
           Per user subordinate group IDs.

       /etc/subuid
           Per user subordinate user IDs.

SEE ALSO         top

       chfn(1), chsh(1), passwd(1), crypt(3), gpasswd(8), groupadd(8),
       groupdel(8), groupmod(8), login.defs(5), subgid(5),
       subuid(5),useradd(8), userdel(8).

COLOPHON         top

       This page is part of the shadow-utils (utilities for managing
       accounts and shadow password files) project.  Information about the
       project can be found at ⟨http://pkg-shadow.alioth.debian.org/⟩.  If
       you have a bug report for this manual page, see 
       ⟨http://pkg-shadow.alioth.debian.org/getinvolved.php⟩.  This page was
       obtained from the project's upstream Git repository 
       ⟨git://anonscm.debian.org/git/pkg-shadow/shadow.git⟩ on 2016-09-01.
       If you discover any rendering problems in this HTML version of the
       page, or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the information
       in this COLOPHON (which is not part of the original manual page),
       send a mail to man-pages@man7.org

shadow-utils 4.3                 09/01/2016                       USERMOD(8)