bu = backup
up = update moodle code within a series to lastest point release
upgrade = upgrade a moodle to next highest release

All scripts must be edited for paths.  They probably will not function as is.
And in case you are wondering, no this server doesn't have a version 3.9 of moodle on it.
So you script kiddies stop trying junk.  Activity like that will get your IP blocked!
Use at your own risk.

SoS, Ken