Git: pre-push confirmation

#!/bin/sh

# An additional confirmation if you really want to push to remote (prevents accidental pushes).
#
# This hook is called with the following parameters:
#
# $1 -- Name of the remote to which the push is being done
# $2 -- URL to which the push is being done
#
# Information about the commits which are being pushed is supplied as lines to
# the standard input in the form:
#
#   <local ref> <local sha1> <remote ref> <remote sha1>

remote="$1"
url="$2"

# If we have a STDIN, use it, otherwise get one
if tty >/dev/null 2>&1; then
    TTY=$(tty)
else
    TTY=/dev/tty
fi

# http://djm.me/ask
ask() {
    while true; do

        if [ "${2:-}" = "Y" ]; then
            prompt="Y/n"
            default=Y
        elif [ "${2:-}" = "N" ]; then
            prompt="y/N"
            default=N
        else
            prompt="y/n"
            default=
        fi

        # Ask the question (not using "read -p" as it uses stderr not stdout)
        echo -n "$1 [$prompt] "

        # Read the answer
        read REPLY < "$TTY"

        # Default?
        if [ -z "$REPLY" ]; then
            REPLY=$default
        fi

        # Check if the reply is valid
        case "$REPLY" in
            Y*|y*) return 0 ;;
            N*|n*) return 1 ;;
        esac

    done
}

# Test the push branch
while read local_ref local_sha remote_ref remote_sha
do

    # Exit if pushed to origin
    if [ "$remote" != "origin" ]
    then
        # Check if not pushing accidentaly
        printf "\n"
        if ask "Do you really want to push to $remote?"; then
            printf 'Pushing.\n\n'
        else
            printf "Cancelling.\n\n"
            exit 1
        fi
    fi
	
done

exit 0