[settings] Add "--quiet" option to "show" command

Allow the "show -q" command to be used to display a setting's value
without also showing its origin and type metadata.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/hci/commands/nvo_cmd.c

diff --git a/src/hci/commands/nvo_cmd.c b/src/hci/commands/nvo_cmd.c
index 70086af..8ac7f58 100644
--- a/src/hci/commands/nvo_cmd.c
+++ b/src/hci/commands/nvo_cmd.c
@@ -43,10 +43,16 @@
  */
 
 /** "show" options */
-struct show_options {};
+struct show_options {
+	/** Do not display setting type, only value */
+	int quiet;
+};
 
 /** "show" option list */
-static struct option_descriptor show_opts[] = {};
+static struct option_descriptor show_opts[] = {
+	OPTION_DESC ( "quiet", 'q', no_argument,
+		      struct show_options, quiet, parse_flag ),
+};
 
 /** "show" command descriptor */
 static struct command_descriptor show_cmd =
@@ -88,7 +94,9 @@
 
 	/* Print setting value */
 	setting_name ( origin, &fetched, name_buf, sizeof ( name_buf ) );
-	printf ( "%s = %s\n", name_buf, value );
+	if ( ! opts.quiet )
+		printf ( "%s = ", name_buf );
+	printf ( "%s\n", value );
 
 	/* Success */
 	rc = 0;