doc: tail: semi-deprecate --sleep-interval and --max-unchanged-stats

Those options are useful only on systems that lack inotify support
and in the unusual event that a system with inotify support must
resort to polling.
* src/tail.c (usage): Note that the --max-unchanged-stats=N and
--sleep-interval=N options are rarely useful on systems with
inotify support.
* doc/coreutils.texi (tail invocation): Likewise.

1 files changed, 3 insertions, 1 deletions

diff --git a/doc/coreutils.texi b/doc/coreutils.texi
index 34d9ff031..76fdce165 100644
--- a/doc/coreutils.texi
+++ b/doc/coreutils.texi
@@ -2821,6 +2821,7 @@ Historical implementations of @command{tail} have required that
 @var{number} be an integer.  However, GNU @command{tail} accepts
 an arbitrary floating point number (using a period before any
 fractional digits).
+When @command{tail} uses inotify, this polling-related option is ignored.
 
 @itemx --pid=@var{pid}
 @opindex --pid
@@ -2855,7 +2856,8 @@ still associated with the same device/inode-number pair as before.
 When following a log file that is rotated, this is approximately the
 number of seconds between when tail prints the last pre-rotation lines
 and when it prints the lines that have accumulated in the new log file.
-This option is meaningful only when following by name.
+This option is meaningful only when polling (i.e., without inotify)
+and when following by name.
 
 @itemx -n @var{k}
 @itemx --lines=@var{k}