commit 5dc74d31244729d1bc51b8b55d1a1c404eac7b99
Author: Marko Turk <mt@markoturk.info>
Date:   Sun Feb 19 20:50:09 2017 +0100

    Fix systat crash on some argument combinations

diff --git a/usr.bin/systat/devs.c b/usr.bin/systat/devs.c
index 3c74fb7..3777487 100644
--- a/usr.bin/systat/devs.c
+++ b/usr.bin/systat/devs.c
@@ -191,6 +191,10 @@ dsmatchselect(const char *args, devstat_select_mode select_mode, int maxshowdevs
 	int i;
 	int retval = 0;
 
+	if (!args) {
+		return(1);
+	}
+
 	/*
 	 * Break the (pipe delimited) input string out into separate
 	 * strings.
@@ -249,6 +253,10 @@ dsselect(const char *args, devstat_select_mode select_mode, int maxshowdevs,
 	int i;
 	int retval = 0;
 
+	if (!args) {
+		return(1);
+	}
+
 	/*
 	 * If we've gone through this code before, free previously
 	 * allocated resources.