Path: utzoo!utgpu!cunews!micor!ecicrl!clewis
From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Newsgroups: comp.periphs.printers
Subject: Re: How do you send NUL to a printer?
Message-ID: <2095@ecicrl.ocunix.on.ca>
Date: 1 Jun 91 06:55:10 GMT
References: <2291@twg.bc.ca>
Organization: Elegant Communications Inc., Ottawa, Canada
Lines: 36

In article <2291@twg.bc.ca> bill@twg.bc.ca (Bill Irwin) writes:
>Inches: ESC C NUL 11    [set to 11 inch form]

>The only difference is the NUL in the inches setting.  The way I
>have been trying to send this is with:

>echo -n "^[C\000011"

The above is a little odd - the "-n" implies a Berkeley style
echo, but \ escapes aren't in Berkeley echo - they are in the
System V echo.

>When this is directed to a file and viewed with vi, I get:

>^[C11

>Is the NUL supposed to show in vi?  When this is sent to the
>printer it behaves as though it was sent the Lines setting
>command, without the NUL.  Is it possible that the NUL is getting
>trapped by the system?

When I try this with a System V echo, the NUL works, but the -n doesn't.
vi *doesn't* show the NUL (even with the "l" command), but it is there.
Run "od -c" on the output and you'll see the null sitting there.  On the
other hand, ^[ *isn't* escape in System V echo.  On my machine (System V,
Xenix machines should be similar), this works:

	echo "\033\000011\c"

Don't rely on vi to show you any sort of reliable representation of
non-printable-ASCII characters.  Use "od" for that.
-- 
Chris Lewis, Phone: (613) 832-0541, Domain: clewis@ferret.ocunix.on.ca
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