bundle exec

Question: why adds bundle exec in the command when running jekyll server in the first time? Answer (short): to know the version of the gems that are going to use.

Note

bundle exec will check the Gemfile to understand ”what gems will be used” and ”which version of the gems should be used”. In the case that Gemfile is modified, run bundle exec jekyll server instead of just running jekyll server.

第一次執行jekyll server要輸入bundle exec jekyll server，讓環境根據 Gemfile 查詢你的程式會用到哪些 gems、並這些 gems 該使用哪些版本。在 Gemfile 沒有更新的情況下，第二次以後直接在環境輸入jekyll server就可以了。

若有修改 Gemfile 的內容，則須重新執行bundle exec jekyll server。

Reference

What does bundle exec rake mean?

You’re running bundle exec on a program. The program’s creators wrote it when certain versions of gems were available. The program Gemfile specifies the versions of the gems the creators decided to use. That is, the script was made to run correctly against these gem versions.