SHELLS(5) BSD Reference Manual SHELLS(5)
shells - shell database
The shells file contains a list of valid shells available on the system. A shell is a command line interpreter that reads user input and executes commands. For each shell a single line should be present, consisting of the shell's path, relative to root. A hash mark ('#') indicates the beginning of a comment; subsequent char- acters up to the end of the line are not interpreted by the routines which search the file. Blank lines are also ignored. The chpass(1) program will not let regular users change their default shell to one not listed in the shells file. The ftpd(8) daemon denies ac- cess to users who are not using one of the listed shells.
/etc/shells
chpass(1), login(1), getusershell(3), nologin(8)
The shells file format appeared in 4.3BSD-Tahoe. MirBSD #10-current June 5, 1993 1