GitHub Actions basics - Commands & Configuration

Introduction

GitHub Actions lets you automate tasks like testing and deploying your code whenever you make changes. It helps you save time by running these tasks automatically without doing them manually.

When you want to automatically test your code every time you push changes to GitHub.

When you want to build and deploy your app to a server or cloud after updating your code.

When you want to run code quality checks or linters on your project automatically.

When you want to automate sending notifications after your code is merged.

When you want to schedule regular tasks like backups or reports using your GitHub repository.

Config File - ci.yml

ci.yml

name: CI

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v3
    - name: Run a one-line script
      run: echo "Hello, world!"

name: Names the workflow for easy identification.

on: Defines when the workflow runs, here on pushes or pull requests to the main branch.

jobs: Contains tasks to run; this example has one job called 'build'.

runs-on: Specifies the environment, here the latest Ubuntu Linux.

steps: Lists actions and commands to execute, starting with checking out the code and then running a simple script.

Commands

Add the GitHub Actions workflow file to the staging area so it can be committed.

Terminal

git add .github/workflows/ci.yml

Expected Output

No output (command runs silently)

Commit the workflow file to your local repository with a clear message.

Terminal

git commit -m "Add GitHub Actions workflow for CI"

Expected Output

[main abc1234] Add GitHub Actions workflow for CI

 1 file changed, 15 insertions(+)

 create mode 100644 .github/workflows/ci.yml

Push your committed workflow file to the main branch on GitHub, triggering the workflow to run.

Terminal

git push origin main

Expected Output

Enumerating objects: 5, done.

Counting objects: 100% (5/5), done.

Delta compression using up to 8 threads

Compressing objects: 100% (3/3), done.

Writing objects: 100% (3/3), 350 bytes | 350.00 KiB/s, done.

Total 3 (delta 1), reused 0 (delta 0), pack-reused 0

remote: Resolving deltas: 100% (1/1), completed with 1 local object.

To github.com:username/repository.git

   def5678..abc1234  main -> main

List recent GitHub Actions workflow runs to check if your workflow started successfully.

Terminal

gh run list

Expected Output

ID    NAME  STATUS  CONCLUSION  EVENT  BRANCH  AGE

12345  CI    completed  success    push   main    1m ago

→

--limit 5 - Show only the 5 most recent workflow runs

View detailed logs of the workflow run with ID 12345 to see the output of each step.

Terminal

gh run view 12345 --log

Expected Output

Run CI



Job build



Step: Checkout repository

  Checked out repository

Step: Run a one-line script

  Hello, world!

→

--log - Show the full logs of the workflow run

Key Concept

If you remember nothing else from this pattern, remember: GitHub Actions runs your automated tasks whenever you push code changes, using workflow files stored in your repository.

Common Mistakes

Placing the workflow file outside the .github/workflows directory

GitHub Actions only detects workflow files inside the .github/workflows folder, so your workflow won't run.

Always save your workflow YAML files inside the .github/workflows directory in your repository.

Using incorrect event names under the 'on' section

If the event names are wrong, the workflow will never trigger when you expect it to.

Use valid event names like 'push' or 'pull_request' exactly as documented.

Not committing and pushing the workflow file to GitHub

The workflow only runs on GitHub, so if the file is not pushed, nothing happens.

After creating or changing the workflow file, commit and push it to the branch you want to trigger the workflow.

Summary

Create a workflow YAML file in .github/workflows to define automated tasks.

Commit and push the workflow file to GitHub to trigger the automation.

Use GitHub CLI commands to check the status and logs of your workflow runs.