Auto update Discord-Canary on Debian

#!/bin/sh
#########################################################################################################
## Script to update Discord automatically instead of waiting for updates at each start                 ##
##                                                                                                     ##
## Original author: BillyGalbreath                                                                     ##
## https://support.discord.com/hc/en-us/community/posts/360031737491-Give-us-an-apt-repository-Linux-  ##
#########################################################################################################

### ensure script is run as root/sudo
if ! [ $(id -u) = 0 ]; then
    if [ "$1" ]; then
        echo "Error: root privileges required"
        exit 1
    fi
    sudo sh $0 "1"
    exit $?
fi

### download and install as root
wget -O /tmp/discord-installer.deb "https://discordapp.com/api/download/canary?platform=linux&format=deb"
dpkg -i /tmp/discord-installer.deb

### execute discord as real user that invoked script
sudo -u `[ $SUDO_USER ] && echo $SUDO_USER || echo $(whoami)` discord-canary