When your book is created on gitbook.com, you need to push some content to it. To do so, you can use the web editor or the command line.
If you want to update your book from the command line, you can use GIT to push your content:
Each book is associated with a Git HTTPS url. The ssh protocol is not yet supported on the GitBook's git server.
The format for the git url is:
https://git.gitbook.com/{{UserName}}/{{Book}}.git
The git server is using your basic GitBook login to authenticate you. When prompted enter your GitBook username and your password (you can also use your API token).
touch README.md SUMMARY.md
git init
git add README.md SUMMARY.md
git commit -m "first commit"
git remote add gitbook https://git.gitbook.com/{{UserName}}/{{Book}}.git
git push -u gitbook master
git remote add gitbook https://git.gitbook.com/{{UserName}}/{{Book}}.git
git push -u gitbook master