There are two problems that I see. First, Clojure expects ns names to use the character - where file names will use the _ character (you cannot use - in ns or _ names in file names); so you need to use
(ns shell-space)
at the top of the file.
Secondly, your script launcher does not use the $ CLASSPATH environment variable, instead it uses $ CLOJURE_CLASSPATH. Emphasize that according to your preferences and everything should be fine.
: .clj , . . ~/dev/projects/ , , ( "shell-space" ). ~/dev/projects/diary/shell, (require 'shell.shell-space).