1.12.2 - Forge missing library files

[Disturbly]

I am on Ubuntu 18.04 and whenever I use the universal .jar installer nothing happens but when run through the terminal I get this:

 

"We appear to be missing one or more essential library files.
You will need to add them to your server before FML and Forge will run successfully.java.lang.ClassNotFoundException: net.minecraft.launchwrapper.Launch
    at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.java:52)
    at net.minecraftforge.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.java:34)"

 

I'm using this for Singleplayer play.