diff --git a/guix/inferior.scm b/guix/inferior.scm
index 629c2c4313..05c8d65deb 100644
--- a/guix/inferior.scm
+++ b/guix/inferior.scm
@@ -87,7 +87,10 @@ (define* (open-inferior directory #:key (command "bin/guix"))
   (define pipe
     (inferior-pipe directory command))
 
-  (setvbuf pipe _IOLBF)
+  (cond-expand
+    ((and guile-2 (not guile-2.2)) #t)
+    (else (setvbuf pipe 'line)))
+
   (match (read pipe)
     (('repl-version 0 rest ...)
      (let ((result (inferior 'pipe pipe (cons 0 rest))))