git global pre-push hook to prevent accidental push to main branch

pre-push

#!/bin/bash

RED="\033[31m";
RESET="\033[0m";
BOLD="\033[1m";

ppid_is_emacs() {
    local command=
    command="$(ps ho comm "$1")"
    [[ "$command" =~ .*emacs.* ]]
}

is_emacs() {
    local temp_ppid=
    temp_ppid="$(ps ho ppid "$1")"
    local ppid="${temp_ppid// /}"
    ppid_is_emacs "$ppid" && return 0
    [ "$ppid" -eq 1 ] &&  return 1
    is_emacs "$ppid" && return 0
    return 1
}

protected_branch="$(git symbolic-ref refs/remotes/origin/HEAD 2>/dev/null | sed -e 's/^refs\/remotes\/origin\///')"
current_branch=$(git symbolic-ref HEAD | sed -e 's,^refs/heads/,,')
REPLY=n
if [[ "$protected_branch" == "" ]]; then
    echo -en "${BOLD}${RED}Can't determine default branch. Continue to push anyway? [y|n] ${RESET}"
    echo -en "${BOLD}"
    if is_emacs "$$"; then echo n; exit 1; fi
    read -n 1 -r < /dev/tty
    echo -en "${RESET}"
elif [ "$protected_branch" == "$current_branch" ]; then
    echo -en "${BOLD}${RED}You're about to push directly to $protected_branch, is that what you intended? [y|n] ${RESET}"
    echo -en "${BOLD}"
    if is_emacs "$$"; then echo n; exit 1; fi
    read -n 1 -r < /dev/tty
    echo -en "${RESET}"
else
    exit 0 # push will execute
fi

echo
if echo $REPLY | grep -E '^[Yy]$' > /dev/null
then
    exit 0 # push will execute
fi
exit 1 # push will not execute