14 Apr 11:52:31 - [red] Uncaught Exception:
14 Apr 11:52:31 - Error: spawn ping EMFILE
    at Process.ChildProcess._handle.onexit (internal/child_process.js:190:19)
    at onErrorNT (internal/child_process.js:362:16)
    at _combinedTickCallback (internal/process/next_tick.js:139:11)
    at process._tickCallback (internal/process/next_tick.js:181:9)
nodered.service: Main process exited, code=exited, status=1/FAILURE
nodered.service: Unit entered failed state.
nodered.service: Failed with result 'exit-code'.
nodered.service: Service hold-off time over, scheduling restart.
Stopped Node-RED graphical event wiring tool.
Started Node-RED graphical event wiring tool.

Some time after that:

pam_unix(sudo:session): session closed for user root
      pi : TTY=unknown ; PWD=/home/pi ; USER=root ; COMMAND=/sbin/iwlist wlan0 scan
pam_unix(sudo:session): session opened for user root by (uid=0)
pam_unix(sudo:session): session closed for user root
14 Apr 12:06:40 - [red] Uncaught Exception:
14 Apr 12:06:40 - Error: spawn ping EMFILE
    at Process.ChildProcess._handle.onexit (internal/child_process.js:190:19)
    at onErrorNT (internal/child_process.js:362:16)
    at _combinedTickCallback (internal/process/next_tick.js:139:11)
    at process._tickCallback (internal/process/next_tick.js:181:9)
nodered.service: Main process exited, code=exited, status=1/FAILURE
nodered.service: Unit entered failed state.
nodered.service: Failed with result 'exit-code'.
nodered.service: Service hold-off time over, scheduling restart.
Stopped Node-RED graphical event wiring tool.
Started Node-RED graphical event wiring tool.
14 Apr 12:07:14 - [info]
Welcome to Node-RED
===================
14 Apr 12:07:14 - [info] Node-RED version: v0.20.3
14 Apr 12:07:14 - [info] Node.js  version: v8.12.0
14 Apr 12:07:14 - [info] Linux 4.14.79+ arm LE
14 Apr 12:07:25 - [info] Loading palette nodes
14 Apr 12:08:20 - [info] Dashboard version 2.13.2 started at /ui

After that:

pi@TimePi:~/.node-red $ node-red-stop

Stop Node-RED
 
Use   node-red-start   to start Node-RED again
 
pi@TimePi:~/.node-red $ lf
lib/           public/                 flows_TimePi.json  package.json       settings.js
node_modules/  flows_TimePi_cred.json  npm_modules.txt    package-lock.json
pi@TimePi:~/.node-red $ rm *.json
pi@TimePi:~/.node-red $ lf
lib/  node_modules/  public/  npm_modules.txt  settings.js
pi@TimePi:~/.node-red $ node-red-start

Start Node-RED
 
Once Node-RED has started, point a browser at http://192.168.0.99:1880
On Pi Node-RED works better with the Firefox or Chrome browser
 
Use   node-red-stop                          to stop Node-RED
Use   node-red-start                         to start Node-RED again
Use   node-red-log                           to view the recent log output
Use   sudo systemctl enable nodered.service  to autostart Node-RED at every boot
Use   sudo systemctl disable nodered.service to disable autostart on boot
 
To find more nodes and example flows - go to http://flows.nodered.org
 
Starting as a systemd service.
Started Node-RED graphical event wiring tool.