CI/CD Commands Cheatsheet - CI/CD Pipeline Debugging Reference

When a CI job sits pending or fails for no clear reason, the reflex is to edit YAML and push again, which is both slow and rarely the cause. A better order exists: confirm the runner is online, that its labels match what the job requested, and that concurrency quota is not exhausted; then read the actual log of the failing step rather than its last line; then decide whether you can reproduce locally and eliminate environment differences one at a time. Low cache hit rates usually come from a key missing the lockfile hash or a path that does not cover the real dependency directory, both diagnosable from configuration alone without restructuring the pipeline. Commands for GitHub Actions, GitLab CI and Jenkins are listed in separate sections, alongside Docker multi-stage builds and general practices. Hung jobs point at infrastructure state; failed jobs point at logs. Most investigations end at one of three places, and naming which one you are in keeps the search short.