Ubuntu Manpages

add-shell

add shells to the list of valid login shells

add-shell shellname [shellname...]

add-shell copies /etc/shells to /etc/shells.tmp, adds the given shells to this file if they are not already present, and copies this temporary file back to /etc/shells.

The shells must be provided by their full pathnames.

specifies the base path under which /etc/shells resides.

shells(5)