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From: lex@philica.ica.philips.nl (Lex van Sonderen)
Newsgroups: comp.windows.news
Subject: wanted: pipe operator example
Message-ID: <755@philica.ica.philips.nl>
Date: 6 Mar 91 15:44:40 GMT
References: <1991Mar5.024148.18582@quorum.com>
Reply-To: lex@leest.ica.philips.nl (Lex van Sonderen)
Organization: Philips TDS, Innovation Centre Aachen
Lines: 26

I want to use the pipe operator to open a shell, send a command,
read the result, send a command, read the result etc...

I do something like this:

/trypipe { % -- -> --
	(/bin/sh) pipe				% readfile writefile
	dup (pwd) writestring			% readfile writefile
	dup flushfile				% readfile writefile
	1 index 100 string readstring {		% readfile writefile str
		==				% readfile writefile
	} {
		pop (nothing\n) ==		% readfile writefile
	} ifelse
% now write some more commands
% ....
	pop pop					% --
} def

Apparently, the operator gets stuck in readstring, no error messages.
Closing the writefile before reading the readfile does help, but I
want to keep it open.
Help!

Lex van Sonderen
lex@ica.philips.nl