bug#9370: "tail -f -1" should work

[Eli the Beareded]

$ tail --version
tail (GNU coreutils) 8.5
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Paul Rubin, David MacKenzie, Ian Lance Taylor,
and Jim Meyering.
$
$ tail -f -1 some.log
tail: option used in invalid context -- 1
$

On any other system I have used the -NUM option can be used with
the -f option to specify how many lines of the file as-is to print
before starting to follow it for updates.

With this version of tail, it always prints ten lines and then
starts the follow.

Elijah