Add rofi example [skip ci] (#651)

Rofi is a linux modal menu for fuzzy filtering, with a similar UX to
Alfred or Spotlight on OSX.

Borrows quite directly from the fzf example.

examples/README.md

@@ -369,3 +369,15 @@ Example usage:
 ``` shell
 $ cat src/babashka/main.clj | bb examples/fzf.clj
 ```
+
+### [rofi](rofi.clj)
+
+Invoke [rofi](https://github.com/davatorium/rofi), a type-to-filter menu on linux, from babashka.
+
+See [rofi.clj](rofi.clj)
+
+Example usage:
+
+``` shell
+$ cat src/babashka/main.clj | bb examples/rofi.clj
+```

examples/rofi.clj

@@ -0,0 +1,12 @@
+(require '[babashka.process :as p])
+
+(defn rofi [s]
+  (let [proc (p/process
+               ["rofi" "-i" "-dmenu" "-mesg" "Select" "-sync" "-p" "*"]
+               {:in  s :err :inherit
+                :out :string})]
+    (:out @proc)))
+
+(rofi (slurp *in*))
+
+;; `echo "hi\nthere\nclj" | bb examples/rofi.clj`