Is there a way to disallow a certain combination of commands and options?

Question

Say, I create a new repo, and try to commit. Git shows me

*** Please tell me who you are.

Run

  git config --global user.email "you@example.com"
  git config --global user.name "Your Name"

to set your account's default identity.
Omit --global to set the identity only in this repository.

Without reading the last line, I run the two lines suggested by git (with --global) and happily commit.

A week later I create a new repo for a completely unrelated project where I'd need to commit under a different user.email. Without even thinking about user.email, I try to commit, it goes through and I push to the origin.

The above happened to me twice and made me think whether there is a way to disallow git config --global.

For example, if I run

git config --global user.email "you@example.com"

I'd like bash not to run the command and show me a warning, but when I run

git config user.email "you@example.com"

I'd like it to go through.

Is it possible?

Answer 1

Simplest is to make a function for this one case (for Bash):

git() {
    for arg in "$@"; do
        if [[ $arg == --global ]]; then
            echo "Don't use '--global'!"
            return 1
        fi
    done 
    command git "$@"
}

Note that that wouldn't check if --global there is actually an option, and not e.g. an option-argument to another option and wouldn't matter in the least if git is run from somewhere other than the shell. Also if you make a git alias to include --global, it won't be caught by this, etc. Obviously you can also circumvent the protection by running command git or /usr/bin/git, or by just undefining the function.