ref: 4772141bd632a56a349a9ea96f908878860ad78a
dir: /clear/
#!/bin/rc
# clears all the output from programs,
# leaving only the command prompts
grep `{echo -n '^'^$prompt(1)} </dev/text | \
grep -v '^'^$prompt(1)^'(clear|"")' | \
uniq >/tmp/clearing.$pid
cp /tmp/clearing.$pid /dev/text
rm -f /tmp/clearing.$pid