View changes between HEAD and previous commit:
git diff HEAD^ HEAD
View changes between HEAD and <commit_id>:
git diff 0232ea938e607942e3e477e4a72e5e7fbf3dc496 HEAD
View changes between HEAD and <commit_id> for specific file:
git diff 0232ea938e607942e3e477e4a72e5e7fbf3dc496 HEAD site.yml