diff --git a/guix/scripts/environment.scm b/guix/scripts/environment.scm
index ec071402f4..ac2c79ab65 100644
--- a/guix/scripts/environment.scm
+++ b/guix/scripts/environment.scm
@@ -420,7 +420,7 @@ (define script
     ;; Script to obtain the list of environment variable values.  On a POSIX
     ;; shell we can rely on 'set', but on fish we have to use 'env' (fish's
     ;; 'set' truncates values and prints them in a different format.)
-    "env || /usr/bin/env || set; echo GUIX-CHECK-DONE; read x; exit\n")
+    "PS1=; env || /usr/bin/env || set; echo GUIX-CHECK-DONE; read x; exit\n")
 
   (define lines
     (match (primitive-fork)