Is there a script to determine Minecraft Server Jar Version?

Question

I'm trying to find a way to determine the Minecraft Server version (ie. 12w40b, 1.4.5, etc) of a given Jar file without needing to start up the entire server process? (I have full control over the server, as I'm writing a basic admin interface)

• Is there a command-line argument I can append to my java -jar ... command to have minecraft only print the version and exit?
• Can I extract the Jar file and look/grep for a specific file?

UPDATE I've created an issue with the Minecraft Bug Tracker here, we'll see what happens from the Mojang team. :)

Answer 1

You cannot do that with the ways you are outlining. You have 2 options:

• Go by the date of the file, provides that you know when which version was released. You can find that here: http://www.minecraftwiki.net/wiki/Version_history
• go by checksum of the version, provides that you have the checksum of each version in a table. You would have to create that first.
• Start the server only until the first line of the output is reached, which outputs the version and kill it immediately.

Answer 2

Although this is an older question, it seems to still be relevant, as I just implemented a solution to this problem myself. I wrote a small bash script that, when passed a path to a minecraft server jar, extracts the MinecraftServer.class file to a temporary location, then extracts the String constants table using the javap tool (requires the JDK to be installed, rather than/in addition to the Java runtime), then filters the table down by looking for the expected Major.Minor.Rev version pattern. This solution works pretty reliably for now, with a couple of caveats:

• Version number must be in Maj.Min.Rev format. Versioning tends to be pretty consistent once applied to a software application, but any changes will break the script.
• Assumes no new additional string constants that match the expected format are present. A future change could very well introduce a "conflicting" string which would likely break the script.

To use the script, simply pass it the path to the minecraft server jar as the only argument. On success, the script returns 0 and outputs the version string to stdout. On failure, the script returns a non zero value.

#!/bin/bash
# Simple bash script that attempts to extract the version number from the
# minecraft server jar file.
#
# This script makes use of the Java dissassembler tool, provided with the
# Java JDK. You may need to explicitly install the JDK, since most server
# installs likely rely solely on the Java runtime (which does not include
# the development tools)

# Temporary file to extract the relevant class file into
TMP_CLASS=$(mktemp /tmp/mc-server-class.XXXXXXXXXXXXXXXX.class)

if [ -z "$1" ]; then
    >&2 echo "ERROR: You must specify a minecraft server jar file"
    exit 1
fi

# Ensure expected external dependencies are present
which unzip >/dev/null
if [ $? -ne 0 ]; then
    >&2 echo "ERROR: This utility requires 'unzip' to be installed"
    exit 2
fi

which javap >/dev/null
if [ $? -ne 0 ]; then
    >&2 echo "ERROR: This utility requires 'javap' to be installed"
    exit 2
fi

# Extract the main server class into the temporary file (we do this since
# javap apparently does not like to slurp from stdout)
unzip -p "$1" net/minecraft/server/MinecraftServer.class >$TMP_CLASS

# Use the java dissassembler tool to extract the constants table. We pipe the
# constants table into grep, and seperate out the Utf8 lines (all the String
# constact values). Next, we pipe the string constants to another grep, looking
# for the expected major.minor.revision number format. Finally, pipe the line
# for the version constant string into sed, to pare it down to a jsut the
# version string itself.
javap -c -verbose $TMP_CLASS | grep 'Utf8' | grep '[0-9]\{1,\}\.[0-9]\{1,\}\(\.[0-9]\{1,\}\)\{0,1\}' | sed -n 's/.*[^0-9.]\([0-9]\{1,\}\.[0-9]\{1,\}\(\.[0-9]\{1,\}\)\{0,1\}\).*/\1/p'

rm $TMP_CLASS
if [ $? -ne 0 ]; then
    >&2 echo "ERROR: Failed to remove temporary class file '${TMP_CLASS}'"
fi

Answer 3

Scripted one-liner approach without extra java packages, directories or created files:

unzip -p server.jar net/minecraft/server/MinecraftServer.class|strings|grep '[0-9]{1,}.[0-9]{1,}(.[0-9]{1,}){0,1}'

Successfully tested on a vanilla 1.13.2 server.jar.

[Apologies, I intended to simply post as a comment to Liam C.'s answer, as this is derivative (thanks for the unzip & grep regex!), but the system won't let me because I'm not legit enough yet.]

Answer 4

This is an old post, but here is an update:

Awnser to your question: No

Rather:

When you open the server you will get this line on the top of the server log:

[hh:mm:ss INFO]: Starting minecraft server version [version number]

You can also find the logs at serverfiles\logs\

Answer 5

You can find the version of Minecraft running by typing about in the server console window.