From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <132f7ab76fee59596efcab59956f6c36@csplan9.rit.edu>
To: 9fans@cse.psu.edu
Date: Mon, 15 Oct 2007 12:46:12 -0400
From: john@csplan9.rit.edu
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Subject: [9fans] newbie rc question
Topicbox-Message-UUID: d0a4ad0c-ead2-11e9-9d60-3106f5b1d025

So, after reading the Blit paper, I thought 'watch' looked pretty
neat and tried to make a simple rc script to act similarly. However,
when I use the script (at the end of this email) to try something
like this:
man -t ls > foo
watch foo | page

page says 'converting from troff to postscript' but then never
actually displays anything. I'm sure there's something basic
I'm forgetting here--can somebody help me figure out what's
wrong?

Here's the code (I apologize if it doesn't meet your standards)


#!/bin/rc
# Watch the specified file for changes; print out the file
# if there are any changes. 

if (~ $#* 1) {
	cat $1
	sum = `{sum $1}
	while () {
		newsum = `{sum $1}
		if (! ~ $sum(1) $newsum(1)) {
			sum = $newsum
			cat $1
		}
		sleep 1
	}
} 
if not {
	echo 'Usage: watch <file>'
}