man page: document when substitutions are applied for RUN and other keys

1 files changed, 6 insertions, 3 deletions

diff --git a/udev.7 b/udev.7
index a7e2f5a4e7..711bd0861b 100644
--- a/udev.7
+++ b/udev.7
@@ -164,10 +164,13 @@ The
 \fBNAME\fR,
 \fBSYMLINK\fR,
 \fBPROGRAM\fR,
-\fBOWNER\fR
-and
+\fBOWNER\fR,
 \fBGROUP\fR
-fields support simple printf\-like string substitutions:
+and
+\fBRUN\fR
+fields support simple printf\-like string substitutions. The
+\fBRUN\fR
+format chars gets applied after all rules have been processed, right before the program is executed. It allows the use of the complete environment set by earlier matching rules. For all other fields, substitutions are applied while the individual rule is being processed. The available substitutions are:
 .TP
 \fB$kernel\fR, \fB%k\fR
 The kernel name for this device.