Suppose that you want to use a non-standard shell as your login shell(for the purposes of this, 'non-standard' means that it's not installedsystem-wide; you have to compile your own version). Further suppose,for the sake of argument, that the shell you want to use doesn't havea command-line option to tell it to be a login shell.

If your shell did have such a command line option, using it as yourlogin shell would be