Re: tail +n does not work under Linux?

[Christophe LYON]

> > Maybe a slight rewording of the man page could highlight this?
> > (eg add another reference to the info page for this trick)
>
> What do you think about the attached patch to the --help output (and thus
> man page)?

Thanks for taking my comment into account!
It is indeed clearer with your proposal, I'll let you decide between 
CNT, COUNT or NUM :-)

I have noticed a typo in my name (it's Christophe).

Would it possible to add a short reference to the info doc inside the 
man page? I know there is already one at the end, but as there is a 
special note about 'tail -CNT', I think that something like:
"Look at the full texinfo manual for a compatibility note for this 
option" could be added at the -c, -n and -f options.

It's a bit heavy, but I think it would help.


> > - tail +COUNT is supported on "older systems". Older than what? How do I
> > know whether I am using a "older system" or not?
>
> "older systems" being those that failed to define _POSIX2_VERSION, or
> defined it to the older value, or when you are using the environment
> variable to select the older behavior.
>
> > Is there a way to know which default POSIX version is used by coreutils?
> > I have check the build logs, and saw nothing.
>
> Look for something like this:
>
> configure:12516: checking for desired default level of POSIX conformance
> configure:12527: result: none-specified
>
> In my case, I neither had the environment variable set at configure time,
> nor did my system headers set _POSIX2_VERSION to either recognized value
> (in other words, my system intentionally admits that it is not yet
> compliant to either version).  I guess there are three accepted values
> these days, now that POSIX 2008 is finalized; maybe our docs need to be
> updated to mention the value required by the latest POSIX version.

I have built coreutils-7.4 under RHEL 3 and 4, and Solaris 8, without 
defining _POSIX2_VERSION before starting the build. In each case, 
configure reported "none-specified", but the Solaris build has chosen a 
different default.

This is confusing when we want to use the same commands on different 
systems. Do you suggest rebuiling with POSIX2_VERSION defined at least 
under Solaris, so that all my environments behave the same?

I would like to be able to know at runtime which is the default chosen, 
it would at least help debugging such issues for users which are not 
very familiar with such things. (I am not very familiar, but more than 
other users)


Thanks for your work,

Christophe.