Carreau Use $() for command substitution instead of backticks/quotes.
One of the example was using quotes instead of backticks.
Backticks are the "older" way of doing things, which has a number of

Here I'm more worried about readability as depending on font and "smart"
editor helping on the web, many people may confuse ` with ', it could
end up modifying formatting on makrdown powered website... etc...
Latest commit 2e87206 Oct 5, 2018

cull-idle Example

The file provides a script to cull and shut down idle single-user notebook servers. This script is used when cull-idle is run as a Service or when it is run manually as a standalone script.

Configure cull-idle to run as a Hub-Managed Service

In, add the following dictionary for the cull-idle Service to the list: = [
        'name': 'cull-idle',
        'admin': True,
        'command': [sys.executable, '', '--timeout=3600'],


  • 'admin': True indicates that the Service has 'admin' permissions, and
  • 'command' indicates that the Service will be managed by the Hub.

Run cull-idle manually as a standalone script

This will run cull-idle manually. cull-idle can be run as a standalone script anywhere with access to the Hub, and will periodically check for idle servers and shut them down via the Hub's REST API. In order to shutdown the servers, the token given to cull-idle must have admin privileges.

Generate an API token and store it in the JUPYTERHUB_API_TOKEN environment variable. Run manually.

    export JUPYTERHUB_API_TOKEN=$(jupyterhub token)
    python3 [--timeout=900] [--url=]