diff --git a/usr.sbin/jail/jail.8 b/usr.sbin/jail/jail.8
index d44b7f66a64eda..a9b076b79d9655 100644
--- a/usr.sbin/jail/jail.8
+++ b/usr.sbin/jail/jail.8
@@ -105,7 +105,9 @@ Exhibit a list of all configured non-wildcard jails and their parameters.
 No jail creation, modification or removal performed if this option is used.
 The
 .Ar separator
-string is used to separate parameters.
+string is used to separate parameters.  If the separator string is empty (''
+or "") then each parameter will be followed by a NUL byte, with one additional
+NUL byte at end of each jail's parameters.
 Use
 .Xr jls 8
 utility to list running jails.
diff --git a/usr.sbin/jail/jail.c b/usr.sbin/jail/jail.c
index 46cabf76ae110c..50cc6fb562bd3a 100644
--- a/usr.sbin/jail/jail.c
+++ b/usr.sbin/jail/jail.c
@@ -978,6 +978,7 @@ print_jail(FILE *fp, struct cfjail *j, int oldcl, int running)
 #endif
 		fputs(separator, fp);
 		print_param(fp, j->intparams[IP_COMMAND], ' ', 0);
+		putc('\n', fp);
 	} else {
 		printsep = 0;
 		if (running) {
@@ -987,13 +988,18 @@ print_jail(FILE *fp, struct cfjail *j, int oldcl, int running)
 		TAILQ_FOREACH(p, &j->params, tq)
 			if (strcmp(p->name, "jid")) {
 				if (printsep)
-					fputs(separator, fp);
+					*separator ? fputs(separator, fp) : putc(0, fp);
 				else
 					printsep = 1;
-				print_param(fp, p, ',', 1);
+				print_param(fp, p, *separator ? ',' : '\n', 1);
 			}
+		if (*separator)
+			putc('\n', fp);
+		else {
+			putc(0, fp);	// end of value line
+			putc(0, fp);	// end of this jail
+		}
 	}
-	putc('\n', fp);
 }
 
 /*
@@ -1038,6 +1044,19 @@ quoted_print(FILE *fp, char *str)
 	int c, qc;
 	char *p = str;
 
+/*
+ * In NUL-delimited mode, output the string as-is with
+ * no quoting or escaping of any characters.
+ */
+
+	if (*separator == 0) {
+		fputs( str, fp );
+		return;
+	}
+
+/*
+ * Otherwise, process it the way we always do:
+ */
 	qc = !*p ? '"'
 	    : strchr(p, '\'') ? '"'
 	    : strchr(p, '"') ? '\''