This is a bash script that will start up a MultiMC instance with a OpenGL recorder like FRAPS in Linux called glc. Simply put your MultiMC folder in the documents folder, then launch this script. Next type in the full name of the MultiMC instance and voila.

gistfile1.sh

#!/bin/sh

while true; do
    read -p "What is the instance name? " instance
    if [ -d ~/Documents/MultiMC/instances/$instance ]
        then
	    dateVar=$(date +%s)
	    clear
            echo
	    echo "-------------------"
            echo "Movies are saved in ~/Movies/"
	    echo "-------------------"
	    echo
	    echo "-------------------"
            echo "Starting MultiMC instance: $instance"
	    echo "-------------------"
            sleep 1
	    cd ~/Documents/MultiMC/instances/$instance/minecraft/
		
	    glc-capture -f 30 -o ~/Movies/java-$dateVar.glc java  -Xms512m -Xmx1024m -jar MultiMCLauncher.jar  "JadarMC" "6113205940204067539" "Minecraft: $instance - glc" "1920x1080" "Mojang"
            

	    echo
	    echo "-------------------"
            echo "Movie file saved at ~/Movies/java-$dateVar.glc"
	    echo "-------------------"

	    break
	else
	    echo
	    echo "Not a valid instance name. Check if capitols are correct."
	    echo
    fi
done