At a command line, cd into the appropriate directory, e.g. [py65](py65/) or [vic20](vic20/).
Execute the c02 compiler from the parent directory using the c02 source file (without the .c02 extension) as an argument.
For example, to compile the program [conds.c02](py65/conds.c02), in the [py65](py65/) directory, use the command
../c02 conds
in Linux, or
..\c02 conds
in Windows.
Some of the subdirectories contain a c02.bat file, which will compile the .c02 program, then run dasm to assemble the code. However, the path to dasm is hardcoded, so you will likely need to change it.
The file [c02.sh](./c02sh) provides the same functionality in Linux, but it may not be in a working state.