Patch from Ned Ludd, solar at gentoo dot org:

I had previously provided you with a patch to help complete busybox's
props suite, but have heard no word back. Sense then I've made use of as
many of busybox's native API settings as I could find and would really
love for you to include support for this. If there is something more I
need to do to get this supported added in please let me know.

include/usage.h

@@ -2266,6 +2266,27 @@
   #define USAGE_IPC_LOG(a)
 #endif
 
+#ifdef CONFIG_SYSCTL
+#define sysctl_trivial_usage \
+	"[OPTIONS]... [VALUE]...\n"
+#define sysctl_full_usage
+	"sysctl - configure kernel parameters at runtime\n\n" \
+	"Options:\n" \
+	"\t-n\tUse this option to disable printing of the key name when printing values.\n" \
+	"\t-e\tUse this option to ignore errors about unknown keys.\n" \
+	"\t-w\tUse this option when you want to change a sysctl setting.\n" \
+	"\t-p\tLoad in sysctl settings from the file specified or /etc/sysctl.conf if none given.\n" \
+	"\t-a\tDisplay all values currently available.\n" \
+	"\t-A\tDisplay all values currently available in table form."
+
+#define sysctl_example_usage
+	"sysctl [-n] [-e] variable ...\n" \
+	"sysctl [-n] [-e] -w variable=value ...\n" \
+	"sysctl [-n] [-e] -a\n" \
+	"sysctl [-n] [-e] -p <file>\t(default /etc/sysctl.conf)\n" \
+	"sysctl [-n] [-e] -A\n"
+#endif
+
 #define syslogd_trivial_usage \
 	"[OPTION]..."
 #define syslogd_full_usage \