How do I force the user to become root

I have a standard function I use in bash for this very purpose:

# Check if we're root and re-execute if we're not.
rootcheck () {
    if [ $(id -u) != "0" ]
    then
        sudo "$0" "$@"  # Modified as suggested below.
        exit $?
    fi
}

There's probably more elegant ways (I wrote this AGES ago!), but this works fine for me.

To use this function consistently in a script, you should pass it the arguments received by the script originally.

Usage: rootcheck "${@}" (rootcheck alone will not pass any arguments to the rootcheck function)

i am using this single line version, easy to copy paste on top of scripts

[ `whoami` = root ] || { sudo "$0" "$@"; exit $?; }

sudo chown root yourcode
sudo chmod 500 yourcode

Voila!