Anyone with read permissions for a repository can test a site locally.
Prerequisites 
Before you can use Jekyll to test a site, you must:
Building your site locally 
- Run - bundle install.
- Run your Jekyll site locally. shell- $ bundle exec jekyll serve > Configuration file: /Users/octocat/my-site/_config.yml > Source: /Users/octocat/my-site > Destination: /Users/octocat/my-site/_site > Incremental build: disabled. Enable with --incremental > Generating... > done in 0.309 seconds. > Auto-regeneration: enabled for '/Users/octocat/my-site' > Configuration file: /Users/octocat/my-site/_config.yml > Server address: http://127.0.0.1:4000/ > Server running... press ctrl-c to stop.- Notes: - If you've installed Ruby 3.0 or later (which you may have if you installed the default version via Homebrew), you might get an error at this step. That's because these versions of Ruby no longer come with - webrickinstalled.- To fix the error, try running - bundle add webrick, then re-running- bundle exec jekyll serve.
- If your - _config.ymlfile's- baseurlfield contains your GitHub repository's link, you can use the following command when building locally to ignore that value and serve the site on- localhost:4000/:shell- bundle exec jekyll serve --baseurl=""
 
- To preview your site, in your web browser, navigate to - http://localhost:4000.
Updating the gem 
Jekyll is an active open source project that is updated frequently. If the github-pages gem on your computer is out of date with the github-pages gem on the server, your site may look different when built locally than when published on . To avoid this, regularly update the github-pages gem on your computer.
- Update the github-pagesgem.- If you installed Bundler, run bundle update github-pages.
- If you don't have Bundler installed, run gem update github-pages.
 
- If you installed Bundler, run