Standalone tools and references. All free, none gated behind an email, none requiring an account.
Git and GitHub answersDirect answers to the questions people actually search, including the error messages they paste verbatim — each linked to the lesson behind it.
Git Command Atlas54 commands across 13 categories, each with a working example, the caution that matters, and a link into the lesson behind it.
Undo a Git commitAmend, reset, revert or rebase — which one, what each destroys, and how to recover.
Choosing a branching strategyThe five questions that decide it, three worked decisions, and the merge-method half.
Git worktreesSeveral branches checked out at once — the interruption workflow without stash.
Git clients & merge toolsWhether a paid GUI or merge tool is worth it, which free tool does the same job, and what this site earns from those links (nothing).
GitHub
Section titled “GitHub”CODEOWNERSPattern syntax, last-match-wins, and the three ways routing fails silently.
Repository rulesetsLayered, admin-enforceable policy over branches and tags.
GitHub CLI (gh)Repositories, pull requests, issues, workflows and the raw API from the terminal.
GitHub APIREST and GraphQL, authentication choices, pagination and pull request automation.
GitHub Actions
Section titled “GitHub Actions”Your first workflowThe tutorial: from an empty .github/workflows to a green check.
Contexts and expressionsEvery context, the expression syntax, and the injection mistake.
CachingKeys, restore-keys, scope and eviction — and when a cache makes things worse.
Example workflowsValidated CI pipelines for Python, Node, Go, Java, .NET, Docker, Terraform and Ansible.
Security
Section titled “Security”GitHub Actions Security ChecklistTen sections, each item naming the attack it prevents, each section citing its primary source. Printable.
OIDC in GitHub ActionsReplace stored cloud keys with a per-run token, and write a trust policy that actually restricts.
Remove secrets from Git historyRotate first; then filter-repo, with everything the rewrite does not fix.
Branch protection as a security boundaryWhat each rule actually prevents, and what none of them touch.
DevOps and GitOps
Section titled “DevOps and GitOps”GitOps explainedThe four principles, the litmus test most pipelines fail, and what reconciliation buys.
Terraform Git workflowBranching, state and environments for infrastructure as code.
Image tagging from GitTags that mean something: SHA, branch, release.
Troubleshooting
Section titled “Troubleshooting”Git Troubleshooting Decision TreeStart from the symptom — undo a commit, recover a branch, escape detached HEAD, fix a rejected push.
Lab: Debug a failing workflowFour Actions failures whose error messages point the wrong way.
Lab: Reset, revert and restoreFive situations, three commands, one that destroys work.
Templates
Section titled “Templates”Free toolkit repositoryCODEOWNERS starter, tested Git aliases, repository health checklist, branching decision matrix.
GitHub Actions Production Workflow VaultTwenty production GitHub Actions workflows plus reusable workflows and a composite action — CI, containers, Terraform, security, releases, Kubernetes, OIDC. Paid.
Professional ToolkitTwenty-nine production-ready templates, checklists and scripts — the paid set, starting where the free ones stop.
Cheat sheets
Section titled “Cheat sheets”Free Git Engineer Cheat Sheet BundleSix printable references: commands, recovery, branching and rebase, pull request review, Actions, and security. No email required.
All hands-on labsTwenty guided scenarios you break and repair in a disposable repository, with real output.
Learning pathsSeven sequenced routes through the curriculum, chosen by where you are now.
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