diff --git a/README.md b/README.md
index 4fc180f4..f3ccd266 100644
--- a/README.md
+++ b/README.md
@@ -22,7 +22,7 @@ conntrack | Shows conntrack statistics (does nothing if no `/proc/sys/net/netfil
 cpu | Exposes CPU statistics | FreeBSD
 diskstats | Exposes disk I/O statistics from `/proc/diskstats`. | Linux
 entropy | Exposes available entropy. | Linux
-filefd | Exposes file descriptor statistics. | Linux
+filefd | Exposes file descriptor statistics from `/proc/sys/fs/file-nr`. | Linux
 filesystem | Exposes filesystem statistics, such as disk space used. | FreeBSD, Linux, OpenBSD
 loadavg | Exposes load average. | Darwin, Dragonfly, FreeBSD, Linux, NetBSD, OpenBSD, Solaris
 mdadm | Exposes statistics about devices in `/proc/mdstat` (does nothing if no `/proc/mdstat` present). | Linux