Tutorials/Linux server update script
Template:ScriptWarning Template:Exclusive
This is a detailed bash script to update a vanilla Minecraft server. Default parameters can be modified within the script, or passed in as parameters. Target installation version will default to the latest release, though any version can be specified.
This script was written on CentOS 7 but should work for any POSIX compliant Linux distribution so long as the dependencies are available.
Dependencies
This script relies on cURL to handle downloading of Mojang manifests and the server JAR file itself. The JSON parser jq is used to extract the relevant information out of the manifests.
On CentOS 7 jq is available through the EPEL repository. On other distributions it may be available, or may require installation from source.
To Install the required dependencies on CentOS 7 perform the following commands
yum update yum -y install epel-release yum -y install curl jq
To Install the required dependencies on a Debian platform perform the following commands
sudo apt-get update sudo apt-get install curl jq -y
Usage
This script only handles updating the server JAR file itself. Should you need to stop the server, change permissions on the newly downloaded file, and start the server again afterwards, a wrapper script is recommended. The following is a simple example wrapper script for a setup using a separate user and group for the server, and a server that is started and stopped through systemd.
Please be cautious. While these scripts worked when originally posted, anyone can edit the wiki, and furthermore your system or setup may be different than was used to create them.
updatemc.sh
#!/bin/sh #------------ # Wrapper for updatemcjar.sh #------------ JAR_PATH="/home/minecraft/server/server.jar" # Change this to point to your server.jar echo "Stopping Minecraft" systemctl stop minecraft echo "Minecraft Stopped" ./updatemcjar.sh --jar-path $JAR_PATH -y chown minecraft:minecraft $JAR_PATH #Change your user & group if needed chmod 750 $JAR_PATH chmod +x $JAR_PATH echo "Starting Minecraft" systemctl start minecraft echo "Minecraft Started"
The main script itself does all the heavy lifting, and has many configurable parameters based upon your setup.
updatemcjar.sh
#!/bin/sh
#----------------------------------------
# A shell script for updating the minecraft server jar file on Linux Servers
# Written by: Andrew Haskell
# Updated by: Zukaro Travon
# Last updated on: 2019.Sep.23
# Distributed under The MIT License (MIT)
#
# Dependencies
# cURL For downloading of the manifest and jar files
# jq For parsing the manifests
#
#
# ---- IMPORTANT ----
# This script merely updates the minecraft server jar.
# Wrap this script in a wrapper script to take care of stopping and
# starting your server based on your setup.
# If you need to change permissions on the final server jar do it from
# within that warpper script as well.
#
# Example Wrapper Script:
# systemctl stop minecraft
# ./updatemcjar.sh -y --jar-path "/srv/minecraft/server.jar"
# sudo chown minecraft:minecraft "/srv/minecraft/server.jar"
# sudo chmod 750 "/srv/minecraft/server.jar"
# sudo chmod +x "/srv/minecraft/server.jar"
# systemctl start minecraft
#----------------------------------------
# Error out script on errors
set -e
# Default Settings (Can be changed through parameters)
TEMP_DIR='/tmp/updatemc/'
JAR_PATH='/home/minecraftuser/minecraftdir/server.jar'
VERSION_MANIFEST='https://piston-meta.mojang.com/mc/game/version_manifest.json'
# Output paths
NORMAL_OUT=/dev/stdout
ERROR_OUT=/dev/stderr
# Parameter Flags
FLAG_FORCE=
FLAG_VERSION=
FLAG_CONFIRM=
FLAG_TEST=
# Help Page
usage()
{
echo
echo "----------------------------------------"
echo "$0 - A tool for updating the minecraft server jar easily"
echo "Written by: Andrew Haskell - Distributed under The MIT License (MIT)"
echo
echo "Dependencies:"
echo " cURL Included in most major distributions package repositories"
echo " jq Check your distribution repositories or build from source"
echo
echo "Usage: $0 [options]"
echo
echo " -f, --force If the Target Version SHA1 matches the current file's SHA1, force the update anyway, implies --yes"
echo " -y, --yes Skip update confirmation"
echo " -v, --version Specify a different target version. Without this parameter, the latest release version is used"
echo " -t, --test Test the Target Version SHA1 against the current file's SHA1 without changing any files"
echo " -s, --silent Suppress script output, implies --yes"
echo " --no-err Suppress error messages (Dangerous!)"
echo " --temp-dir Specify a different temporary directory, default is $TEMP_DIR"
echo " --jar-path Specify a different final JAR path, default is $JAR_PATH"
echo " --manifest Specify a different version manifest URL, default is $VERSION_MANIFEST"
echo " -h, --help Print this help message"
echo
echo "Examle Usage:"
echo " $0 Run the script normally"
echo " $0 -f Force update the existing JAR"
echo " $0 -v 1.8.1 -y Update to 1.8.1 without asking for confirmation"
echo
echo "----------------------------------------"
echo
}
# Check Script Parameters
while [ "$1" != "" ]; do
case $1 in
-f | --force ) FLAG_FORCE=1
FLAG_CONFIRM=1
;;
-v | --version ) shift
FLAG_VERSION=$1
;;
-y | --yes ) FLAG_CONFIRM=1
;;
-s | --silent ) NORMAL_OUT=/dev/null
FLAG_CONFIRM=1
;;
--no-err ) ERROR_OUT=/dev/null
;;
--temp-dir ) shift
TEMP_DIR=$1
;;
--jar-path ) shift
JAR_PATH=$1
;;
--manifest ) shift
VERSION_MANIFEST=$1
;;
-t | --test ) FLAG_TEST=1
;;
-h | --help ) usage
exit
;;
* ) echo "Bad option specified"
usage
exit 1
;;
esac
shift
done
echo "Clearing temp directory: $TEMP_DIR" > $NORMAL_OUT
mkdir -p $TEMP_DIR
DOWNLOADED_JAR="${TEMP_DIR}server.jar"
if [ -e $DOWNLOADED_JAR ]
then
rm -f $DOWNLOADED_JAR
fi
echo "Downloading Version Manifest from: $VERSION_MANIFEST" > $NORMAL_OUT
VERSION_MANIFEST_DATA=$(curl -s "$VERSION_MANIFEST")
echo "Done" > $NORMAL_OUT
echo "Parsing Version Manifest" > $NORMAL_OUT
VERSION_LATEST=$(echo "$VERSION_MANIFEST_DATA" | jq -r '.latest.release' )
VERSION_TARGET=$VERSION_LATEST
echo "Latest released version: $VERSION_LATEST" > $NORMAL_OUT
if [ -n "$FLAG_VERSION" ]
then
VERSION_TARGET=$FLAG_VERSION
echo "Target version to download: $VERSION_TARGET" > $NORMAL_OUT
fi
PACKAGE_MANIFEST=$(echo "$VERSION_MANIFEST_DATA" | jq -r --arg VERSION_TARGET "$VERSION_TARGET" '.versions | .[] | select(.id==$VERSION_TARGET) | .url')
echo "Done" > $NORMAL_OUT
if [ -z "$PACKAGE_MANIFEST" ]
then
echo "Could not find target version: $VERSION_TARGET within the manifest file. Was the target version incorrectly specified? If not then double check the Mojang version manifest by hand" > $ERROR_OUT
exit 1
fi
echo "Downloading Package Manifest from: $PACKAGE_MANIFEST" > $NORMAL_OUT
PACKAGE_MANIFEST_DATA=$(curl -s "$PACKAGE_MANIFEST")
echo "Done" > $NORMAL_OUT
echo "Parsing Package Manifest" > $NORMAL_OUT
SERVER_NEWJAR_URL=$(jq -rn --argjson url "$PACKAGE_MANIFEST_DATA" '$url.downloads.server.url')
SERVER_NEWJAR_SHA1=$(jq -rn --argjson sha1 "$PACKAGE_MANIFEST_DATA" '$sha1.downloads.server.sha1')
echo "Done" > $NORMAL_OUT
echo "Calculating SHA1 of $JAR_PATH" > $NORMAL_OUT
SERVER_OLDJAR_SHA1=$(sha1sum "$JAR_PATH" | cut -d " " -f 1)
echo "Old JAR SHA1: $SERVER_OLDJAR_SHA1" > $NORMAL_OUT
echo "New JAR SHA1: $SERVER_NEWJAR_SHA1" > $NORMAL_OUT
if [ "$SERVER_OLDJAR_SHA1" = "$SERVER_NEWJAR_SHA1" ]
then
echo "SHA1 sums match. $JAR_PATH is already target version" > $NORMAL_OUT
if [ -z "$FLAG_TEST" ]
then
if [ -z "$FLAG_FORCE" ]
then
echo "Exiting" > $NORMAL_OUT
exit
else
echo "Forcing JAR Update" > $NORMAL_OUT
fi
else
exit
fi
else
echo "SHA1 sums mis-matched. $JAR_PATH differs from target version." > $NORMAL_OUT
if [ -z "$FLAG_TEST" ]
then
if [ -z "$FLAG_CONFIRM" ]
then
while true; do
read -p "Replace $JAR_PATH with latest? [y/n]: " yn
case $yn in
[Yy]* ) break
;;
[Nn]* ) echo "Exiting"
exit
;;
* ) echo "Please answer Y(es) or N(o)"
;;
esac
done
fi
else
exit
fi
fi
echo "Downloading new server JAR from: $SERVER_NEWJAR_URL to $DOWNLOADED_JAR" > $NORMAL_OUT
curl -s -L -f -o $DOWNLOADED_JAR $SERVER_NEWJAR_URL
echo "Done" > $NORMAL_OUT
echo "Calculating SHA1 of $DOWNLOADED_JAR" > $NORMAL_OUT
DOWNLOADED_SHA1=$(sha1sum $DOWNLOADED_JAR | cut -d " " -f 1)
echo "Dwn JAR SHA1: $DOWNLOADED_SHA1" > $NORMAL_OUT
echo "New JAR SHA1: $DOWNLOADED_SHA1" > $NORMAL_OUT
if [ "$DOWNLOADED_SHA1" = "$SERVER_NEWJAR_SHA1" ]
then
echo "SHA1 sums match, proceeding" > $NORMAL_OUT
else
echo "SHA1 sums mis-matched, check downloaded JAR at: $DOWNLOADED_JAR" > $ERROR_OUT
exit 1
fi
JAR_PATH_BACKUP=${JAR_PATH}.bak
echo "Renaming $JAR_PATH to $JAR_PATH_BACKUP" > $NORMAL_OUT
mv $JAR_PATH $JAR_PATH_BACKUP
echo "Copying $DOWNLOADED_JAR to $JAR_PATH" > $NORMAL_OUT
cp $DOWNLOADED_JAR $JAR_PATH
echo "Re-Verifying $JAR_PATH" > $NORMAL_OUT
FINAL_SHA1=$(sha1sum $JAR_PATH | cut -d " " -f 1)
if [ "$FINAL_SHA1" = "$SERVER_NEWJAR_SHA1" ]
then
echo "$JAR_PATH updated successfully to version: $VERSION_TARGET" > $NORMAL_OUT
exit
else
echo "SHA1 sums mis-matched, current JAR at: $JAR_PATH does NOT match the version attempting to be installed. Rolling Back" > $ERROR_OUT
echo "Deleting $JAR_PATH" > $ERROR_OUT
rm -f $JAR_PATH
echo "Copying backup JAR from: $JAR_PATH_BACKUP to $JAR_PATH" > $ERROR_OUT
cp $JAR_PATH_BACKUP $JAR_PATH
echo "Original JAR file restored. Please check the files in $TEMP_DIR" > $ERROR_OUT
exit
fi