TIL: Show File from Branch in Git

This is an interesting one I learned while setting up a /draft-gitlab-release skill. Since I manually bump version numbers in this project, it's important to compare the live version number first, so I don't accidentally double-bump the version number on development.

I normally use git checkout master && cat box.json | grep version to quickly check the version number. However, this is a bit unwieldy as it requires switching branches, and often requires stashing my local changes as well.

In drafting this skill, GitHub Copilot recommended the git show command instead. The syntax is:

git show <branch_name>:<file_path>

This will display the contents of the specified file from the specified branch without checking out the branch at all!

Using this and jq to parse the version numbers, I can quickly compare version numbers between development and main:

developmentVersion="$(jq -r '.version' box.json)"
mainVersion="$(git show main:box.json | jq -r '.version')"