Oh Git is complex!

Git is a complex system. To see the proof check out:

Prooved. ;)

To mitigate that we are going to get inside the head of Linus Torvalds ! (Just a little bit maybe into a single neuron), and, in this part, we will focus on configurations. I always thought that to understand a system I need to understand it's configurations (or even better it's installation).

When I get to a new company the first thing I try to figure out is:

How do I install this? How do I configure this?

How does Linus Torvalds think?

Everything is a file

Yes this is how Linus thinks: everything is a file

As Linus loves this everything is a file, you can just view git configurations as a file.

So if we manage to get which files Linus uses in git we might be able to penetrate into oh-my-complex-git!

3 Fallback layers of config

1. System - Your OS git config - git config --system

2. Global - Your User git config - git config --global

3. Local - Your Repository git config - git config --local



git config --system # => /etc/gitconfig git config --global # => ~/.gitconfig or ~/.config/git/config git config --local # => .git/config

Git first read git config from .git/config -> [fallback to] ~/.gitfconfig -> [fallback to] /etc/gitconfig

Email per repo

So if you have different email addresses for different repository this goes into .gitconfig == git config --local

Get the global config: git config --list --global

➜ tmp git config --list --global user.name = Tomer Ben David user.email = tomer.bendavid@ohohoh.com core.autocrlf = input format.pretty = format:%h %Cblue%ad%Creset %ae %Cgreen%s%Creset

Would that be the same as cat ~/.gitconfig what do you think?



➜ tmp cat ~/.gitconfig [ user] name = Tomer Ben David email = tomer.bendavid@ohohoh.com [ core] autocrlf = input [ format] pretty = format:%h %Cblue%ad%Creset %ae %Cgreen%s%Creset

Yes and no! different notation but generally the same!

Get the merged config: git config --list

The merged config is the combination of all configs with the hierarchy, let's see it on my machine ;)



git config --list ➜ tmp git config --list core.excludesfile = ~/.gitignore core.legacyheaders = false core.quotepath = false mergetool.keepbackup = true push.default = simple color.ui = auto color.interactive = auto repack.usedeltabaseoffset = true alias.s = status alias.a =! git add . && git status alias.au =! git add -u . && git status alias.aa =! git add . && git add -u . && git status alias.c = commit alias.cm = commit -m alias.ca = commit --amend alias.ac =! git add . && git commit alias.acm =! git add . && git commit -m alias.l = log --graph --all --pretty = format: '%C(yellow)%h%C(cyan)%d%Creset %s %C(white)- %an, %ar%Creset' alias.ll = log --stat --abbrev-commit alias.lg = log --color --graph --pretty = format: '%C(bold white)%h%Creset -%C(bold green)%d%Creset %s %C(bold green)(%cr)%Creset %C(bold blue)<%an>%Creset' --abbrev-commit --date = relative alias.llg = log --color --graph --pretty = format: '%C(bold white)%H %d%Creset%n%s%n%+b%C(bold blue)%an <%ae>%Creset %C(bold green)%cr (%ci)' --abbrev-commit alias.d = diff alias.master = checkout master alias.spull = svn rebase alias.spush = svn dcommit alias.alias =! git config --list | grep 'alias\.' | sed 's/alias\.\([^=]*\)=\(.*\)/\1\ => \2/' | sort include.path = ~/.gitcinclude include.path = .githubconfig include.path = .gitcredential diff.exif.textconv = exif credential.helper = osxkeychain user.name = Tomer Ben David user.email = tomer.bendavid@ohohohoh.com core.autocrlf = input format.pretty = format:%h %Cblue%ad%Creset %ae %Cgreen%s%Creset

That was it ALL the git config on my machine, you have it! I hope I didn't put any password there ;) If I did please let me know, code review guys, this is importanto!

git config --local/global/system user.name - get a single config

Ask layer by layer for a config



➜ tmp git config --local user.name fatal: BUG: setup_git_env called without repository # We called from a non-repository folder. ➜ tmp git config --global user.name Tomer Ben David ➜ tmp git config --system user.name # => nothing in the global config file. ➜ tmp

Aha! so it's coming from the global (user) config!

Note that in the file it's with [user] and the name, and the git config returns the combined name user.name

if you need a hierarchy larger than 3 then in the file it will look like:



[ branch "gke" ] remote = origin merge = refs/heads/gke

so this one should be branch.gke.remote , let's verify this:



➜ .git git: ( gke ) git config branch.gke.remote # => yes it is branch.gke.remote! origin

Set a new config with git config mysection.mykey myvalue

➜ .git git: ( gke ) git config mysection.mykey myvalue ➜ .git git: ( gke ) git config mysection.mykey myvalue

So we were able to set it let's look at the file:



➜ .git git: ( gke ) cat config [ core] repositoryformatversion = 0 filemode = true bare = false logallrefupdates = true ignorecase = true precomposeunicode = true [ remote "origin" ] url = https://bitbucket.org/yshenbaum/k8s-course.git fetch = +refs/heads/ * :refs/remotes/origin/ * [ branch "gke" ] remote = origin merge = refs/heads/gke [ mysection] ##### =====> Here it is! see the section in [] mykey = myvalue

Summary

You now know actually exactly where your git config files are this is very helpful and much more explainable then using the git commands. Rereading this post not sure was able to simplify, but it makes some sense, at least some sense at the end of the day for us programmers! One last note

Resources

Ry's Git Tutorial (BOOK)