I'm trying to write a function to reas a file's content as a string

(use ports)

(define (read-file-contents filename)
  (call-with-output-string
    (lambda (result-string)
      (call-with-input-file
        filename
        (lambda (source-file)
          (copy-port source-file result-string))))))

(display (read-file-contents "/home/karol/.zshrc"))