@example
tail [@var{option}]@dots{} [@var{file}]@dots{}
tail -@var{number} [@var{option}]@dots{} [@var{file}]@dots{}
-tail +@var{number} [@var{option}]@dots{} [@var{file}]@dots{}
+tail +@var{number} [@var{option}]@dots{} [@var{file}]@dots{} # obsolescent
@end example
If more than one @var{file} is specified, @code{tail} prints a
the @sc{gnu} @code{tac} command.
@code{tail} accepts two option formats: the new one, in which numbers
-are arguments to the options (@samp{-n 1}), and the old one, in which
-the number precedes any option letters (@samp{-1} or @samp{+1}).
+are arguments to the options (@samp{-n 1}), and the obsolescent one, in
+which the number precedes any option letters (@samp{-1} or @samp{+1}).
+Warning: support for the @samp{+1} form will be withdrawn, as future
+versions of @sc{posix} will not allow it.
If any option-argument is a number @var{n} starting with a @samp{+},
@code{tail} begins printing with the @var{n}th item from the start of
@samp{k}, @samp{m}) as in @code{-c}, or @samp{l} to mean count by lines,
or other option letters (@samp{cfqv}).
+Warning: the @samp{+@var{count}} usage is obsolescent. Future versions
+of @sc{posix} will require that support for it be withdrawn. Use
+@samp{-n +@var{count}} instead.
+
@item -c @var{bytes}
@itemx --bytes=@var{bytes}
@opindex -c
characters.)
@item +@var{pos1}[-@var{pos2}]
-The obsolete, traditional option for specifying a sort field. The field
+The obsolescent, traditional option for specifying a sort field. The field
consists of the line between @var{pos1} and up to but @emph{not including}
@var{pos2} (or the end of the line if @var{pos2} is omitted). Fields
and character positions are numbered starting with 0. See below.
+Warning: the @samp{+@var{pos}} usage is obsolescent. Future versions of
+@sc{posix} will require that support for it be withdrawn. Use
+@option{-k} instead.
+
@end table
In addition, when @sc{gnu} @code{sort} is invoked with exactly one argument,
Here are some examples to illustrate various combinations of options.
In them, the @sc{posix} @samp{-k} option is used to specify sort keys rather
-than the obsolete @samp{+@var{pos1}-@var{pos2}} syntax.
+than the obsolescent @samp{+@var{pos1}-@var{pos2}} syntax.
@itemize @bullet
Skip @var{n} characters before checking for uniqueness. If you use both
the field and character skipping options, fields are skipped over first.
+Warning: the @samp{+@var{n}} usage is obsolescent. Future versions of
+@sc{posix} will require that support for it be withdrawn. Use @samp{-s
+@var{n}} instead.
+
@item -c
@itemx --count
@opindex -c