diff --git a/lib/gen_cmd.py b/lib/gen_cmd.py
index 52f255a..eb2a63f 100644
--- a/lib/gen_cmd.py
+++ b/lib/gen_cmd.py
@@ -280,7 +280,7 @@
 
 def shell_cmd(command_string,
               quiet=None,
-              print_output=1,
+              print_output=None,
               show_err=1,
               test_mode=0,
               time_out=None,
@@ -360,6 +360,7 @@
 
     # Assign default values to some of the arguments to this function.
     quiet = int(gm.dft(quiet, gp.get_stack_var('quiet', 0)))
+    print_output = int(gm.dft(print_output, not quiet))
     ignore_err = int(gm.dft(ignore_err, gp.get_stack_var('ignore_err', 1)))
 
     err_msg = gv.svalid_value(command_string)