gem install jekyll
jekyll serve --watch

http://127.0.0.1:4000/

Jekyll basic Usage

$ jekyll build
# => The current folder will be generated into ./_site

$ jekyll build --destination <destination>
# => The current folder will be generated into <destination>

$ jekyll build --source <source> --destination <destination>
# => The <source> folder will be generated into <destination>

$ jekyll build --watch
# => The current folder will be generated into ./_site,
#    watched for changes, and regenerated automatically.