名称

       usermod - 修改一个用户账户

大纲

       usermod [选项] 登录

描述

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

选项

       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.

       -b, --badnames
           Allow names that do not conform to standards.

       -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
           用户的新登录目录。

           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
           密码过期之后，账户被彻底禁用之前的天数。

           0 表示密码过期时，立即禁用账户；-1 表示不使用这个功能。

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

       -g, --gid GROUP
           用户的新初始登录组的组名或数字代号。此组必须存在。

           用户主目录中，属于原来的主组的文件将转交新组所有。

           主目录之外的文件所属的组必须手动修改。

       -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
           将用户的主目录移动到新位置。

           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.

           您应该确保密码符合系统的密码政策。

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

       -P, --prefix PREFIX_DIR
           Apply changes in the PREFIX_DIR directory and use the configuration files from the
           PREFIX_DIR directory. 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.

       -s, --shell SHELL
           用户的新登录 shell 的名称。将此字段设置为空会让系统选择默认的登录 shell。

       -u, --uid UID
           用户 ID 的新数值。

           This value must be unique, unless the -o option is used. The value must be
           non-negative.

           用户的邮箱，用户主目录中属于此用户的文件的属主 ID 也将自动更改。

           用户主目录之外文件所有权必须手动修复。

           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-subuids 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-subuids 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-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.

       -w, --add-subgids 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-subgids 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-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.

       -Z, --selinux-user SEUSER
           用户登陆的 SELinux 用户。

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

CAVEATS

       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. On other platforms it only uses
       utmp to check if the user is logged in.

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

       您必须更改 NIS 服务器上的 NIS 相关内容。

配置文件

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

       LASTLOG_UID_MAX (number)
           Highest user ID number for which the lastlog entries should be updated. As higher user
           IDs are usually tracked by remote user identity and authentication services there is
           no need to create a huge sparse lastlog file for them.

           No LASTLOG_UID_MAX option present in the configuration means that there is no user ID
           limit for writing lastlog entries.

       MAIL_DIR (string)
           邮箱目录。修改或删除用户账户时需要处理邮箱，如果没有指定，将使用编译时指定的默认值。

       MAIL_FILE (string)
           定义用户邮箱文件的位置(相对于主目录)。

       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).

           默认值是 0，意味着组中的成员数没有限制。

           此功能(分割组)允许限制组文件中的行长度。这对于确保 NIS 组的行比长于 1024 字符。

           如果要强制这个限制，可以使用 25。

           注意：分割组可能不受所有工具的支持(甚至在 Shadow 工具集中)。您不应该使用这个变量，除非
           真的需要。

       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 65536.

       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 65536.

文件

       /etc/group
           组账户信息。

       /etc/gshadow
           安全组账户信息。

       /etc/login.defs
           Shadow 密码套件配置。

       /etc/passwd
           用户账户信息。

       /etc/shadow
           安全用户账户信息。

       /etc/subgid
           Per user subordinate group IDs.

       /etc/subuid
           Per user subordinate user IDs.

参见

       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).