In Bash, how to add “Are you sure [Y/n]” to any command or alias?

Question

In this particular case, I\'d like to add a confirm in Bash for

Are you sure? [Y/n]

for Mercurial\'s hg push ssh://username@www.example.com//some

Answer 1

Late to the game, but I created yet another variant of the confirm functions of previous answers:

confirm ()
{
    read -r -p "$(echo $@) ? [y/N] " YESNO

    if [ "$YESNO" != "y" ]; then
        echo >&2 "Aborting"
        exit 1
    fi

    CMD="$1"
    shift

    while [ -n "$1" ]; do
        echo -en "$1\0"
        shift
    done | xargs -0 "$CMD" || exit $?
}

To use it:

confirm your_command

Features:

• prints your command as part of the prompt
• passes arguments through using the NULL delimiter
• preserves your command's exit state

Bugs:

• echo -en works with bash but might fail in your shell
• might fail if arguments interfere with echo or xargs
• a zillion other bugs because shell scripting is hard