add-shell - add shells to the list of valid login shells

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.

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

       add-shell - add shells to the list of valid login shells

shells(5)

                                                   23 Sep 2021                                      ADD-SHELL(8)

add-shellshellname [shellname...]