Cool git thing I learned today: In Git 2.13, you can have conditional includes to set certain options based on the directory you’re in. So, I have the following in my main .gitconfig

[includeIf "gitdir:~/src/project_dir/"]
  path = ~/src/project_dir/.gitconfig_include

and ~/src/project_dir/.gitconfig_include sets my work email, allowing my consulting email to be used everywhere else.

[user]
  name = August Lukens
  email = august@company.com

More info here: https://git-scm.com/docs/git-config#_conditional_includes