Minecraft server update script for Paper using API v2

update-server.sh

#!/bin/bash
serverpath="" #Server directory goes here

#Create update directory if it doesn't exist
if [ ! -d "$serverpath/update" ]; then
        mkdir $serverpath/update
fi

#Check for server updates
cd $serverpath/update
version="" #Minecraft version goes here (e.g. "1.16.5")
URL="https://papermc.io/api/v2/projects/paper/versions/$version"
latestbuild=$(curl $URL | awk -F ',' '{print $NF}' | sed 's/]}//')
remoteversion="paper-$version-$latestbuild.jar"
if ! [[ $remoteversion == $(cat currentversion.txt) ]] ; then
        echo "Downloading update..."
        curl $URL/builds/$latestbuild/downloads/$remoteversion --remote-name
        echo $remoteversion > currentversion.txt
        mv *.jar ../paper.jar
        echo "New server jar installed."
else
        echo "Server is up-to-date."
fi