adduser

Adduser is a command used to create new user accounts on Unix-like operating systems, most commonly Debian and its derivatives. It is part of the adduser package and provides a friendlier interface than the lower-level useradd tool. In Debian-based systems, adduser is a Perl script located at /usr/sbin/adduser and typically delegates account creation to useradd with a set of sane defaults.

Interactive behavior: When run without arguments, adduser asks for the username and details such as full name (GECOS), room number, work phone, and home phone. It can also prompt to set a password. Upon completion, adduser creates the user's home directory under /home/username (copied from /etc/skel), assigns initial permissions, and updates system databases.

Non-interactive usage and options: Users can specify parameters on the command line, such as the home directory, login shell, and additional account attributes. A common option is --disabled-password to create the account without forcing a password, useful for later password setup. The exact option set may vary by distribution.

Configuration and consequences: The defaults are governed by /etc/adduser.conf and /etc/login.defs. The UID and GID ranges, whether new users are added to common groups, and other defaults are defined there. Creating an account updates /etc/passwd, /etc/shadow, and /etc/group, and places a skeleton home in /home/username.

See also: useradd, adduser.conf, /etc/skel.