Basic linux tools for deploy_hook

[ThomDietrich]

Hey there, I need to use the deploy_hook functionality to copy generated certificates to a place and name which another application expects. To that end I've defined something similar to this:

certificates:
  - domains:
       - ui.kntinternet.de
     deploy_hook: cp /etc/letsencrypt/live/mydomain.de/privkey.pem /etc/letsencrypt/privkey.pem

Upon execution I receive the error:

  dnsrobocert-1  | Hook 'deploy-hook' reported error code 1
  dnsrobocert-1  | Hook 'deploy-hook' ran with error output:
  dnsrobocert-1  |  /bin/sh: 1:  cp: not found

Could you please provide basic commands like cp with the container? Thanks!