Fix rupa#262 by separating new PROMPT_COMMAND commands

z.sh

@@ -247,6 +247,11 @@ elif type complete >/dev/null 2>&1; then
     [ "$_Z_NO_PROMPT_COMMAND" ] || {
         # populate directory list. avoid clobbering other PROMPT_COMMANDs.
         grep "_z --add" <<< "$PROMPT_COMMAND" >/dev/null || {
+            # Check if there are existing PROMPT_COMMANDs that are not terminated with a semicolon
+            if [[ "$PROMPT_COMMAND" =~ ^[^\ ]+ ]] && ! [[ "$PROMPT_COMMAND" =~ ^.*\;\ *$ ]]
+                then # terminate it
+                PROMPT_COMMAND="$PROMPT_COMMAND; "
+            fi
             PROMPT_COMMAND="$PROMPT_COMMAND"$'\n''(_z --add "$(command pwd '$_Z_RESOLVE_SYMLINKS' 2>/dev/null)" 2>/dev/null &);'
         }
     }