Re: [Expectperl-discuss] Tab translation difference between AIX and Linux

[Christoph S. <csc...@am...>]

Hello Austin,

first of all, thanks for your input. In Germany Friday and Monday were 
public holidays :)) hence I'm catching up now.

exp...@li... wrote on 13-04-2006 
18:33:30:

> On Thu, Apr 13, 2006 at 04:59:38PM +0200, Christoph Schwaiger wrote:
> > Hello,
> > 
> > after looking some time into documentation about terminals and ttys, 
I'm 
> > still not any further. I guess I need help.
> > 
> > In my setup I use expect to spawn shells (rsh to AIX), (ssh to Linux), 
to 
> > a lot of remote shells in parallel. So far so good, there is no 
problem 
> > with that. Only, when talking to something like 30 boxes, the 
connection 
> > closure takes a while, but OK, that's all.
> > 
> 
>    You could use scp/rcp to copy the files, then diff them. If you have
> a bastion you can do ssh hostone 'scp hosttwo file .'; scp 'hostone file 
.',
> or something of that nature. ssh/rsh/scp/rcp can be setup to allow 
automatic
> login.
> 
surely, that is possible without change to the ssh trusted environment, as 
I do rsh and ssh already without pw, the copy should work without change. 
(The setup for ssh, the /.ssh folder with the keys and authorized hosts is 
a bit of a pain when apache runs as nobody, as this user has no login and 
~, but it works)

The issue is, as I don't compare only files, but also command outputs 
(i.e. the content of a app shared mem segment, printed by appropriate app 
interface), I would need to: 1) use command to print output into a file 
locally, 2) copy the file over and 3) delete it there. This is possible, 
no doubt, but creates a new dependency a shell doesn't have: it needs a 
known fs (i.e. /tmp) to have free space left. Thus, I try to go for 
something else.

> 
> > The thingy described before (called shiva) is called by another one 
called 
> > (egalite) to retrieve output from many hosts and compare the gathered 
> > files. My problem is when comparing files coming from AIX (5.2) boxes 
to 
> > files coming from Linux (suse 9.? on Itanium), that the diff doesn't 
match 
> > because TAB (x09) is translated on AIX boxes, but not on Linux. A hack 

> > would be to give diff the option to ignore whitespaces, but this will 
> > cause problems on another side, hence don't like it really.
> 
>    There is probably a setting to tell the aix tty not to do that.
> `man stty` on the aix host.
>    alternatively you could translate the file using something like
> uuencode, then decode on the local box and feed to diff.
> 
The tty translation capabilities I checked as one of the first things, but 
the whole difference between them are the parameter ignpar and istrip 
which are deactivated on AIX, but activated on Linux (it seems like Linux 
uses the same settings here as "raw" on AIX). But this parameters are not 
related to tab translation for what I understand.

All I was looking for was an obvious problem I overlooked (somebody else 
should have fallen over it by now), but it seems not to be the case.
What I'll do then it probably letting the perl script doing the diff do 
some post processing to translate the tab. That seems to be at the moment 
the easiest thing to do. As far as I remember there is a comment saying 
something like at the end of character translaction lies madness - will 
see :)
 
> > As I assume to talk to remote boxes of different types has probably 
done 
> > by somebody... (but if somebody has compared the output already?)... I 

> > hope that somebody has found a solution to this one already. That 
would be 
> > great! 
> > 
> > Otherwise, I guess a cat need to postprocess the output rather. That 
will 
> > do the trick too..
> > 
> > Thanks in advance.
> > 
> > Christoph Schwaiger.
> > 
> > PS: If somebody knows a good documentation covering the whole data 
path 
> > from the perl expect through the pseudo tty, to the process, to the 
> > remshell and so on...feel free to make me aware of it! 
> 
>    Unix ptys are fairly widely documented, but I'm sure we could do
> with a summary in the docs.
> 
>    Austin
> 
Thanks a lot!

Christoph Schwaiger
> 
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