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@(#)adduser.8 6.4 (Berkeley) 10/01/87

C 4 adduser - procedure for adding new users A new user must choose a login name, which must not already appear in /etc/passwd or /usr/lib/aliases. It must also not begin with the hyphen (``-'') character. An account can be added by editing a line into the passwd file; this must be done with the password file locked e.g. by using vipw (8).

A new user is given a group and user id. User id's should be distinct across a system, since they are used to control access to files. Typically, users working on similar projects will be put in the same group. Thus at UCB we have groups for system staff, faculty, graduate students, and a few special groups for large projects. System staff is group \*(lq10\*(rq for historical reasons, and the super-user is in this group.

A skeletal account for a new user \*(lqernie\*(rq would look like:

ernie::235:20:& Kovacs,508E,7925,6428202:/mnt/grad/ernie:/bin/csh

The first field is the login name \*(lqernie\*(rq. The next field is the encrypted password which is not given and must be initialized using passwd (1). The next two fields are the user and group id's. Traditionally, users in group 20 are graduate students and have account names with numbers in the 200's. The next field gives information about ernie's real name, office and office phone and home phone. This information is used by the finger (1) program. From this information we can tell that ernie's real name is \*(lqErnie Kovacs\*(rq (the & here serves to repeat \*(lqernie\*(rq with appropriate capitalization), that his office is 508 Evans Hall, his extension is x2-7925, and this his home phone number is 642-8202. You can modify the finger (1) program if necessary to allow different information to be encoded in this field. The UCB version of finger knows several things particular to Berkeley - that phone extensions start \*(lq2-\*(rq, that offices ending in \*(lqE\*(rq are in Evans Hall and that offices ending in \*(lqC\*(rq are in Cory Hall. The chfn (1) program allows users to change this information.

The final two fields give a login directory and a login shell name. Traditionally, user files live on a file system different from /usr. Typically the user file systems are mounted on a directories in the root named sequentially starting from from the beginning of the alphabet, eg /a, /b, /c, etc. On each such file system there are subdirectories there for each group of users, i.e.: \*(lq/a/staff\*(rq and \*(lq/b/prof\*(rq. This is not strictly necessary but keeps the number of files in the top level directories reasonably small.

The login shell will default to \*(lq/bin/sh\*(rq if none is given. Most users at Berkeley choose \*(lq/bin/csh\*(rq so this is usually specified here. The chsh (1) program allows users to change their login shell to one of the shells in the approved list given in /etc/shells.

It is useful to give new users some help in getting started, supplying them with a few skeletal files such as .profile if they use \*(lq/bin/sh\*(rq, or .cshrc and .login if they use \*(lq/bin/csh\*(rq. The directory \*(lq/usr/skel\*(rq contains skeletal definitions of such files. New users should be given copies of these files which, for instance, arrange to use tset (1) automatically at each login.

/etc/passwd password file

/usr/skel skeletal login directory

passwd(1), finger(1), chsh(1), chfn(1), aliases(5), passwd(5), vipw(8) User information should be stored in its own data base separate from the password file.