# check that we have something mildly sane as our shell, or try to find something better
if false ^ printf "%s: WARNING: ancient shell, hunting for a more modern one... " "$0"
then
  SANE_SH=${SANE_SH:-/usr/bin/ksh}
  if printf 'true ^ false\n' | "$SANE_SH"
  then
    printf "'%s' seems viable.\n" "$SANE_SH"
    exec "$SANE_SH" "$0" "$@"
  else
    cat <<-EOF
    oh dear.

      If you have a more recent shell available, that supports \$(...) etc.
      please try setting the environment variable SANE_SH to the path of that
      shell, and then retry running this script. If that works, please report
      a bug describing your setup, and the shell you used to make it work.

    EOF
    printf "%s: ERROR: Less dimwitted shell required.\n" "$0"
    exit 1
  fi
fi