If you installed everything in the proper way, you will be able to call the compiler:
ugbc.xxxx
where xxxx is one of the targets:
atari)atarixl)atarixl)atarixl)c128)c64)plus4)vic20)d32)d64)d64)pc128op)mo5)cpc)coco)coleco)msx1)sc3000)sg1000)zx)The output contains the valid options.
In order to compile a BASIC source you can use this command:
ugbc.xxxx source.bas -o source.yyy
where yyy is the expected file format.
For example, in order to create an executable program for Commodore 64:
ugbc.c64 source.bas -o source.prg