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From: sun@me.utoronto.ca (Andy Sun Anu-guest)
Newsgroups: comp.unix.questions,comp.unix.wizards
Subject: Re: get terminal speed from shell script
Message-ID: <90Aug13.095129edt.18647@me.utoronto.ca>
Date: 13 Aug 90 13:51:41 GMT
References: <90Aug12.135618edt.18763@me.utoronto.ca> <1990Aug13.005849.23223@jarvis.csri.toronto.edu>
Organization: University of Toronto, Department of Mechanical Engineering
Lines: 56

In article <1990Aug13.005849.23223@jarvis.csri.toronto.edu> ruhtra@turing.toronto.edu (Arthur Tateishi) writes:
>In artcle <90Aug12.135618edt.18763@me.utoronto.ca> sun@me.utoronto.ca (Andy Sun Anu-guest) writes:
>
>>Is there a way to get the terminal speed from a (sh or csh) script?
>>I used to be able to do the following in a Bourne shell script:
>>			speed=`stty speed`
>>and got the terminal speed assigned to variable speed. As various OS
>>gets updated (e.g. Ultrix 3.1 and SUN OS 4.0.3), this won't work anymore
>>because all stty outputs are being sent to stderr, not stdout, thus no
>>piping or redirection is possible. Is there any similar commands that can 
>>get terminal speed inside a shell script?
>
>I find it odd that the SUN man pages still specify option info is output
>on stdout...  Maybe I shouldn't be surprised.
>

I guess it depends on which version of SUN OS. "speed=`stty speed`" works
for a Sun 3/60 running (I think) SUN OS 3.x. So it does went through stdout.
I tried the same thing on a SPARCstation running Sun OS 4.0.3c and it
gave me "Operation not supported on socket". What you suggested below, i.e,
"speed=`stty speed 2>&1 1>/dev/tty` works on the SPARCstation.

>However, I since stty seems to go bonkers when stdout goes to something
>other than a proper tty device, I came up with the following.
>		speed=`stty speed 3>&2 2>&1 1>&3` 
>This essentially swaps stdout and stderr with a dangling file descriptor 3
>which could be closed with 3>&- however it shouldn't matter. Be warned,
>if stderr has been modified to be a socket going somewhere, it will likely
>blow up with 'stty: Operation not supported on socket.' so you could use
>		speed=`stty speed 2>&1 1>/dev/tty` 
>which also has its drawbacks. 
>Sorry, I can't confirm this for Ultrix. 

I confirmed it, neither works :-)
speed=`stty speed` gave me "Not a typewriter" and
speed=`stty speed  2&1 1>/dev/tty` echoes the speed on the screen but assigns
nothing to the variable speed. I don't know why it works for SPARCstation
because I think /dev/tty is not the same as stdout. If in a C program you
specify /dev/tty as your output stream instead of stdout, everything echoes
on the screen in both cases but you cannot use redirection with /dev/tty.

>
>-- 
>``Sex and drugs? They're nothing compared with a good proof!''
>                                - A Cambridge student  (r.h.f)
>Arthur Tateishi                 g9ruhtra@zero.cdf.utoronto.edu


Will they ever home on a standard on this one? (sighed)

Andy

_______________________________________________________________________________
Andy Sun                            | Internet: sun@me.utoronto.ca
University of Toronto, Canada       | UUCP    : ...!utai!me!sun
Dept. of Mechanical Engineering     | BITNET  : sun@me.utoronto.BITNET