Comment 3 for bug 1707977

Oh joy, a bug in the work-around (and no way to edit the post).
Please add "-a" to the egrep command line to avoid a warning due to the nul terminator in cmdline.

CORRECTED work-around for .bashrc :

i_am_toplevel() {
  case "$SHLVL" in
    1) return 0 ;;
    3) return 1 ;;
    2) # HACK FOR Ubuntu 16.10, 17.04 ... where SHLVL=2 at top
       if egrep -as '(terminal-server|^xterm)' /proc/$PPID/cmdline ; then
         return 0
       fi
       ;;
  esac
  return 1
}