Piping a subprocesses output directly to stdout (java/clojure)

gistfile1.txt

; this is not async
(defn shell
  [cmd]
  (->> (.. Runtime getRuntime (exec cmd) getInputStream)
       java.io.InputStreamReader.
       java.io.BufferedReader.
       line-seq
       (map str)))
       
; or this is async, use this as script to test it:
$ cat dumb.sh
#!/bin/bash

for i in 1 2 3 4 5
do
    echo "Loop iteration $i"
    sleep 2
done
;this is the function
(defn run-proc
  [proc-name arg-string callback]
  (let [pbuilder (ProcessBuilder. (into-array String [proc-name arg-string]))
        process (.start pbuilder)]
    (with-open [reader (clojure.java.io/reader (.getInputStream process))]
      (loop []
        (when-let [line (.readLine ^java.io.BufferedReader reader)]
          (callback line)
          (recur))))))
          
 ; Testing:
 
(run-proc "./dumb.sh" "" println)
About to start...
Loop iteration 1
Loop iteration 2
Loop iteration 3
Loop iteration 4
Loop iteration 5