How to modify a bash alias to take input from the terminal?

Question

In my .bashrc, I have aliases:

#Custom aliases
alias gta="git add -A"
alias gtc="git commit -m 'Added files' "

I want to create a new alias that does the command git push origin <branch name>. Earlier it was easy because it was always set to git push origin master.

But now , GitHub has changed master to main for all repositories created after October 2020. Now what I want is that I want to set an alias gtp and it asks me a prompt to use main or master. Depending on the selection, I want the appropriate commands to be executed.

P.S: I know that we can make 2 aliases , one for master and one for main, but just out of curiosity, how to solve the above problem?

Answer 1

You could add something like this in your .bashrc:

alias gtp=f

f() {
  arg="$1"
  if [[ -z "$arg" ]] || [[ "$arg" != main && "$arg" != master ]]; then
    echo "Bad argument"
  else
    git push origin "$arg"
  fi
}

Then

~$ . .bashrc

$ gtp
Bad argument

$ gtp foo
Bad argument

$ gtp main
<git doing it's thing>

$ gtp master
<git doing it's thing>

Or @Kusalananda's suggestion

f() {
    arg="$1"

    case $arg in
        main|master)
            git push origin "$arg"
            ;;
        *)
            echo error >&2
    esac
}