Cmd-return "launches" whatever line the cursor is on. It's analogous to what return does in a shell console. Ctrl-return and double-clicking do the same thing.
When you launch a $... shell command it executes it and inserts the results. When you launch a url, it opens it in the browser. When you launch a dir path it lets you navigate the dir contents, etc.
When you launch a $... shell command it executes it and inserts the results. When you launch a url, it opens it in the browser. When you launch a dir path it lets you navigate the dir contents, etc.