From af6436559c2954d7f35b7fec29dfcbaa4ebdc03b Mon Sep 17 00:00:00 2001 From: Jim Meyering Date: Mon, 7 Sep 2009 22:10:10 +0200 Subject: tail: ignore -f for piped-stdin, as POSIX requires * src/tail.c (main): Tailing a pipe "forever" is not useful, and POSIX specifies that tail ignore the -f when there is no file argument and stdin is a FIFO or pipe. So we do that. In addition, GNU tail excludes "-" arguments from the list of files to tail forever, when the associated file descriptor is connected to a FIFO or pipe. Before this change, ":|tail -f" would hang. Reported by Ren Yang and Ulrich Drepper. * tests/tail-2/pipe-f: Test for this. * tests/tail-2/pipe-f2: Ensure tail doesn't exit early for a fifo. * tests/Makefile.am (TESTS): Add these tests. * NEWS (POSIX conformance): Mention it. --- NEWS | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'NEWS') diff --git a/NEWS b/NEWS index a5a60948e..7d4f7e203 100644 --- a/NEWS +++ b/NEWS @@ -46,6 +46,12 @@ GNU coreutils NEWS -*- outline -*- cp --reflink accepts a new "auto" parameter which falls back to a standard copy if creating a copy-on-write clone is not possible. +** POSIX conformance + + tail -f now ignores "-" when stdin is a pipe or FIFO, per POSIX. + Now, :|tail -f terminates immediately. Before, it would block indefinitely. + [the old behavior dates back to the original implementation] + * Noteworthy changes in release 7.5 (2009-08-20) [stable] -- cgit v1.2.3-54-g00ecf