Pádraig Brady wrote: >> Subject: [PATCH 1/2] doc: describe how kernel inotify support affects tail -f >> >> * doc/coreutils.texi (tail invocation) [-f]: Mention how inotify >> kernel support makes a difference. >> Prompted by http://bugzilla.redhat.com/662900 >> --- >> doc/coreutils.texi | 5 +++++ >> 1 files changed, 5 insertions(+), 0 deletions(-) >> >> diff --git a/doc/coreutils.texi b/doc/coreutils.texi >> index 289c0ba..dfaf4c9 100644 >> --- a/doc/coreutils.texi >> +++ b/doc/coreutils.texi >> @@ -2830,6 +2830,11 @@ tail invocation >> Likewise, the @option{-f} option has no effect for any >> operand specified as @samp{-}, when standard input is a FIFO or a pipe. >> >> +With kernel inotify support, output is asynchronous and generally very >> prompt. > > That's a little ambiguous to me. > Inotify is async wrt time but sync wrt data change. > How about: > > "With kernel inotify support, output is triggered by file changes > and generally very prompt." > >> +Otherwise, @command{tail} sleeps for one second between checks--- >> +use @option{--sleep-interval=@var{N}} to change that default---which can >> +make the output appear slightly less responsive or bursty. > > One can also specify sub second intervals: > I've had this alias for years: alias tail='tail -s.1'
Thanks for the feedback. How about this? >From 8b5e05bd01774bcb04f7c47646e00b65a00a25ab Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A1draig=20Brady?= <[email protected]> Date: Tue, 24 May 2011 06:44:24 +0200 Subject: [PATCH] doc: improve tail -f vs. inotify description and advice * doc/coreutils.texi (tail invocation): Adjust, and add an example. --- doc/coreutils.texi | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-) diff --git a/doc/coreutils.texi b/doc/coreutils.texi index fa7e015..869ec8b 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -2830,10 +2830,17 @@ tail invocation Likewise, the @option{-f} option has no effect for any operand specified as @samp{-}, when standard input is a FIFO or a pipe. -With kernel inotify support, output is asynchronous and generally very prompt. +With kernel inotify support, output is triggered by file changes +and generally very prompt. Otherwise, @command{tail} sleeps for one second between checks--- use @option{--sleep-interval=@var{n}} to change that default---which can make the output appear slightly less responsive or bursty. +When using tail without inotify support, you can make it more responsive +by using a sub-second sleep interval, e.g., via an alias like this: + +@example +alias tail='tail -s.1' +@end example @item -F @opindex -F -- 1.7.5.2.1.g56b30
