PaperMC startup script

start.sh

#!/bin/bash
set -e

VERSION=1.20.4

LATEST_JSON=$(curl -X 'GET' \
    "https://api.papermc.io/v2/projects/paper/versions/$VERSION/builds" \
    -H 'accept: application/json' \
    | jq '.builds | last ')

BUILD=$(echo $LATEST_JSON \
    | jq -r '.build')

JAR=$(echo $LATEST_JSON \
    | jq -r '.downloads.application.name')

echo "Latest Paper version: $JAR"

if [[ ! -f "$JAR" ]]; then
    wget "https://api.papermc.io/v2/projects/paper/versions/$VERSION/builds/$BUILD/downloads/$JAR"
else
    echo "Already have latest version"
fi

screen -amdS paper java \
    -Xms12G \
    -Xmx18G \
    -XX:+UseG1GC \
    -XX:+ParallelRefProcEnabled \
    -XX:MaxGCPauseMillis=200 \
    -XX:+UnlockExperimentalVMOptions \
    -XX:+DisableExplicitGC \
    -XX:+AlwaysPreTouch \
    -XX:G1NewSizePercent=40 \
    -XX:G1MaxNewSizePercent=50 \
    -XX:G1HeapRegionSize=16M \
    -XX:G1ReservePercent=15 \
    -XX:G1HeapWastePercent=5 \
    -XX:G1MixedGCCountTarget=4 \
    -XX:InitiatingHeapOccupancyPercent=20 \
    -XX:G1MixedGCLiveThresholdPercent=90 \
    -XX:G1RSetUpdatingPauseTimePercent=5 \
    -XX:SurvivorRatio=32 \
    -XX:+PerfDisableSharedMem \
    -XX:MaxTenuringThreshold=1 \
    -Dusing.aikars.flags=https://mcflags.emc.gs \
    -Daikars.new.flags=true \
    -jar $JAR \
    --nogui