/etc/shells
The shells file resides in /etc.
shells5
Shell database
Overview
The shells file contains a list of the shells on the system. 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 characters up to the end of the line are not interpreted by the routines which search the file. Blank lines are also ignored.
Files
Releases
Unchanged in 163 releases since Mac OS X 10.0.