Re: No arguments to diff

[Bob Proulx]

Aaron Yoshitake wrote:
> I'm sorry, running diff --help gave a message that says to report any bugs
> to this email.

My mistake for not saying "Thank you for your report" in my original
message.  I didn't mean to imply that your report of the problem
wasn't appreciated.  I was simply trying to give an accurate
description of things.  It really is appreciated that you took the
time and effort to write us about a bug.

> I downloaded this port of diff from sourcefourge
> <http://gnuwin32.sourceforge.net/packages/diffutils.htm>, which I
> thought to be GNU.

Ah!  GnuWin32!  That helps to know.  They provide a port of many GNU
programs to MS.

I know this can be confusing to people not completely immersed in the
topic.  If you bear with me a moment let me explain briefly.  GNU is a
project to develop a complete Unix-like operating system which is Free
Software.

  http://www.gnu.org/

Therefore by itself GNU is a complete system that does not depend upon
any other.  But also being Free Software everyone has the freedom to
port the programs from the GNU system to other operating systems.
They can do this even to non-free systems such as MS systems.  There
are several different organizations such as GnuWin32 and Cygwin and
others that desire to make programs from the GNU project available on
these other systems and have a quite useful set of programs ported.
This port can be done better in some cases or worse in others
primarily because of differences in capabilities of the underlying
operating system.  In some cases it is impossible to completely
implement a program due to deficiencies in the port-to system.  Many
people have used small parts of GNU software out of context but have
never used a GNU system where those parts were designed to operate!

So from the viewpoint from a user on a system such as MS this is a GNU
program.  But from the perspective of a GNU user it is a retrofitted
program because someone else ported the software to a non-GNU system
which by necessity requires many invasive changes to the program
making it quite a bit different.

Now back to your problem with diff.exe from GnuWin32.
I see on the main GnuWin32 page here:

  http://gnuwin32.sourceforge.net/

A link to their help page says:

  Bugs (errors when executing programs from GnuWin32) can be reported to
  the  [Bugs list]. Please use this list only for bugs, and not as a
  substitute list for asking questions. Use this only for bugs related
  to the GnuWin32 port; report bugs relating to the package itself, to
  the package maintainers (see the homepage mentioned on the GnuWin32
  package page).

  http://sourceforge.net/tracker/?func=browse&group_id=23617&atid=379173

The problem with the --help and --version text is that it was written
for the GNU system.  There has been discussion about whether porters
should change the bug reporting address when making a port.  Some
think they should and some think they shouldn't.  Certainly for any
bugs in the core program the upstream would like to know about it.  At
the moment there isn't any specific recommendation for porters and
there isn't consensus on which should be done and most porters leave
the upstream address in place.

How does someone tell the difference between bugs in an upstream
program and bugs in a port?  That can be difficult for someone who
isn't familiar with the internal workings.  So don't worry about it.

> Thanks for your time, and sorry for the mistake.

Please, it was no problem.  Instead let me apologize for not making
you feel welcome here.  That was my mistake.

Reading your original message again:
> Whenever I run the diff.exe file with no arguments, I get the correct
> messages about not having enough arguments, but then my command prompt
> stops responding, and the program never terminates, making me close
> it. This is quite irritating, since I lose all the information in my
> command window prior to using diff. Is this a known problem, or
> something wrong with my system?

Try pressing Control-C.  This should interrupt the program and return
you to the command prompt.  You shouldn't need to close the window and
therefore wouldn't lose your terminal window history.

On GNU and Unix systems Control-C tells the tty driver to send an
interrupt signal to the foreground process.  MS doesn't have the same
concepts but I think it should work there too even though it is
implemented differently.

Bob