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

This may be a little too short, but for my own private use, it works great

read -n 1 -p "Push master upstream? [Y/n] " reply; 
if [ "$reply" != "" ]; then echo; fi
if [ "$reply" = "${reply#[Nn]}" ]; then
    git push upstream master
fi

The read -n 1 just reads one character. No need to hit enter. If it's not a 'n' or 'N', it is assumed to be a 'Y'. Just pressing enter means Y too.

(as for the real question: make that a bash script and change your alias to point to that script instead of what is was pointing to before)