bug#52077: tail: a case where -n is not taken as implicit

[Shehu Dikko]

Package: coreutils
Version: 9.0

Do please take a look at this example:

% printf '%s\n' just three lines | tee >f1 f2
% tail -n1 f1
lines
% tail -n1 f*
==> f1 <==
lines

==> f2 <==
lines
% tail -1 f1
lines
% tail -1 f*
tail: option used in invalid context -- 1
% tail --version | head -1
tail (GNU coreutils) 9.0

Note that with head and busybox tail, the outputs are unsurprising:

% head -1 f*
==> f1 <==
just

==> f2 <==
just
% head --version | head -1
head (GNU coreutils) 9.0
% busybox tail -1 f*
==> f1 <==
lines

==> f2 <==
lines
%
% uname -v
#1 SMP Debian 4.19.194-3 (2021-07-18)

regards,

s h e h u