--ui flag is incompatible with any explicit commands, like `transcript`

[aryairani]

unison [-v|--version] [(-c|--codebase CODEBASE/PATH) | (-C|--codebase-create CODEBASE/PATH)] 
              [--exit] [--runtime-path DIR] [--lsp-format] 
              [COMMAND | [--token STRING] [--host STRING] [--port NUMBER] [--allow-cors-host STRING]
                [--ui DIR] [-p|--path .path.in.codebase] [--no-file-watch]]

this makes writing launcher scripts hard; is there any reason to not just ignore it?

[aryairani]

We should in general have a way for users to override system-specific settings. Options:

• accept multiple copies of a command, preferring the last
• set environment variables only if they are not already in the environment
• other?