Answer
The argocd CLI manages apps: `argocd app list`, `argocd app get <name>`, `argocd app sync <name>`, `argocd app diff <name>`, `argocd app history`, and `argocd app rollback`. It's used for automation and troubleshooting alongside the web UI and the declarative Application CRs.
argocd app get guestbook
argocd app sync guestbook
argocd app diff guestbookReal-world example An engineer runs `argocd app diff` in CI to preview changes before approving a production sync.