.

diff --git a/doc/sh-utils.texi b/doc/sh-utils.texi
index 434c51daad016bc2aa283c6c26a1c564fe66e907..7d6134b09c193f3911a46532168fbd7030bf7275 100644 (file)
--- a/doc/sh-utils.texi
+++ b/doc/sh-utils.texi
@@ -2320,6 +2320,15 @@ current time and date.  @var{datestr} can be in almost any common
 format.  It can contain month names, timezones, @samp{am} and @samp{pm},
 @samp{yesterday}, @samp{ago}, @samp{next}, etc.  @xref{Date input formats}.
 
+@item -r @var{file}
+@itemx --reference=@var{file}
+@opindex -r
+@opindex --reference
+Display the time and date as obtained from a reference @var{file},
+instead of the current time and date.  Each file has a few timestamps
+associated with it.  In this context, the time and date of the last
+modification are used.
+
 @item -f @var{datefile}
 @itemx --file=@var{datefile}
 @opindex -f