ADDUSER(8) | System Manager's Manual | ADDUSER(8)

# NAME

`adduser`, `rmuser` — add and delete users from the system

# SYNOPSIS

`adduser` | [`-batch` username [group[,group] ...] [fullname] [password]] [`-check_only`] [`-class` login_class] [`-config_create`] [`-dotdir` directory] [`-e` method | `-encryption` method] [`-group` login_group] [`-h` | `-help` | `-?`] [`-home` partition] [`-message` file] [`-noconfig`] [`-shell` shell] [`-s` | `-silent` | `-q` | `-quiet`] [`-uid_start` uid] [`-uid_end` uid] [`-v` | `-verbose`] [`-unencrypted`]

`rmuser` | [username]

# DESCRIPTION

The `adduser` program adds new users to the system. The `rmuser` program removes users from the system. When not passed any arguments, both utilities operate in interactive mode and prompt for any required information.

The options are as follows:

`-batch` username [group[,group] ...] [fullname] [password]
  Enter batch mode in which multiple users are specified on the command line in a compact format. By default the password is assumed to already be properly encrypted.
`-check_only`
  Check the passwd, group, and shells databases for consistency and problems then exit without performing any other operation.
`-class` login_class
  Use the specified login_class as the default user login class. See login.conf(5) for further details.
`-config_create`
  Create or edit default configuration information and message file before proceeding with the normal interactive adduser procedure.
`-dotdir` directory
  Copy files from directory into the HOME directory of new users. Files named in the fashion of “dot.foo” will be renamed to “.foo”. By default, all files are made writable and readable by their owner.
`-encryption`, `-e` method
  Encrypt local passwords using method of encryption as described in login.conf(5). If method is “auto”, the encryption type will be derived from the user's login class.
`-group` login_group
  Specify the default login group. A value of USER means that the username is to be used as the login group.
`-help`, `-h`, `-?`
  Print a summary of options and exit.
`-home` partition
  Specify the default home partition where all users' home directories are to be located.
`-message` file
  Send new users a welcome message from file. Specifying a value of “no” for file causes no message to be sent to new users.
`-noconfig`
  Do not read the default configuration file.
`-shell` shell
  Specify the default shell for new users.
`-silent`, `-s`, `-quiet`, `-q`
  Causes the program to print fewer warnings, questions, and bug reports.
`-uid_start` uid
  Use UIDs from uid up when automatically generating UIDs.
`-uid_end` uid
  Do not use UIDs higher than uid when generating UIDs.
`-unencrypted`
  Causes the program to assume that the password given in batch mode is unencrypted. The password will be encrypted before being added to the password file. Use of this option is discouraged, as the username and cleartext password will appear in the process list, which is visible to users.
`-verbose`, `-v`
  Causes the program to print many warnings and questions. This option is recommended for novice users.

`adduser` first performs consistency checks on the password, group, and shell databases. This includes finding any duplicate user or group names, illegal shells, or shells that aren't executable. Once these tests are passed, `adduser` performs the following operations for each new user:

1. Add the appropriate entries to the password and group files and re-generate the password database using pwd_mkdb(8).
2. Create a home directory and copy all files from the skeletal login directory (normally /etc/skel) to this new directory. Files named in the fashion of “dot.foo” will be renamed to “.foo” in the new directory.
3. Mails the new user a welcome message at the discretion of the account creator.

Similarly, when removing a user, `rmuser` performs the following operations for the given username:

1. Removes any crontab(1) entries or at(1) jobs belonging to the user.
2. Removes the user from the password database and all groups in the group database. If a group becomes empty and its name is the same as the username, the group is removed (this complements `adduser`'s unique per-user groups).
3. Recursively deletes all files in the user's home directory and removes the directory itself (provided the directory actually belongs to the user). `rmuser` prompts for confirmation before actually doing this.
4. Removes the user's incoming mail file if one exists.

Understandably, `rmuser` politely refuses to remove users whose UID is 0 (typically root).

# RESTRICTIONS

username
  It is recommended that login names contain only lowercase characters and digits. They may also contain uppercase characters, non-leading hyphens, periods, underscores, and a trailing ‘`$`’. Login names may not be longer than 31 characters. If you need a longer login name for email addresses, you can define an alias in /etc/mail/aliases.
fullname
  This should contain the user's first name and surname. The ‘`:`’ is not permitted.
login_class
  The specified user login class must exist in /etc/login.conf.
shell
  Only valid entries from the shells(5) database or entries corresponding to pppd(8) are permitted.
uid_start
  This value is the start of the range where free UID values are searched for. This value must be less than the value of uid_end. The default value is 1000 or as configured in the configuration file.
uid_end
  This value is the end of the range where free UID values are searched for. This value must be more than the value of uid_start. The default value is 2147483647 or as configured in the configuration file.
gid/login group
  This value is generated automatically, but can be specified at the discretion of the person invoking the program.
password
  If not empty, the password is encrypted according to login.conf(5). If empty, the account will be automatically disabled to prevent spurious access to it.

# CONFIGURATION

`adduser` follows these steps to extract its configuration information:

1. Read internal variables.
2. Read configuration file (/etc/adduser.conf).
3. Parse command-line options.

The adduser.conf format is explained within that file and is quite straightforward. The configuration file will be created the first time `adduser` is run.

# FILES

/etc/master.passwd
  user database
/etc/group
  group database
/etc/group.bak
  backup of original group database
/etc/shells
  shell database
/etc/ptmp
  lock file for the passwd database
/etc/adduser.conf
  configuration file for `adduser`
/etc/adduser.conf.bak
  backup of original configuration file
/etc/adduser.message
  message file for `adduser`
/etc/adduser.message.bak
  backup of original message file
/etc/skel
  skeletal login directory
/var/log/adduser
  log file for `adduser`

# EXAMPLES

Start `adduser` in interactive mode:

`# adduser`

Create user “falken” and login group “falken”. Invite user “falken” into groups “guest”, “staff”, and “beer”. Realname (fullname) is “Prof. Falken”. The password has been created using encrypt(1):

    # adduser -batch falken guest,staff,beer 'Prof. Falken' \
        '$2b$10$aOadQNznQ1YJFnqNaRRneOvYvZAEO7atYiTND3EsLf6afHT5t1UIK'

Create user “vehlefanz” in login group “guest”. Start the free UID search at 5000. No other groups, no realname, no password. Send a welcome message:

    # adduser -uid_start 5000 -group guest \
        -message /etc/adduser.message -batch vehlefanz

Create user “jsmith” and place in the “jsmith” login group. Also add to the “staff” group. No password:

`# adduser -group USER -batch jsmith staff`

# SEE ALSO

chpass(1), finger(1), passwd(1), setlogin(2), aliases(5), group(5), login.conf(5), passwd(5), shells(5), nologin(8), pwd_mkdb(8), vipw(8), yp(8)

February 18, 2022 | Debian