Feed The Beast
Available Enviroment variables:
OPS = Elevate specified user to ops privileges on first start.
MODPACK = Which modpack server to download.(the name must match what is listed at https://www.feed-the-beast.com/modpacks, ie: FTB Presents SkyFactory 3)
LEVEL = World name of your choosing.
UPDATE = Whether or not the server should look for an update on start.
MOTD = This message shows up in the MC server listings.
JVM_OPTS = default is "-Xms2048m -Xmx2048m".