<<cpif>>=
#!/bin/rc
#
# Based on shell script by Norman Ramsey
# Translated from sh to rc by Russ Cox
#
# see /sys/src/cmd/noweb/COPYRIGHT
#
# cpif [ -eq -ne ] file...
# copy standard input to each of the named files
# if new * old is true or old doesn't exist;
# * defaults to -ne

rfork en

# set -x
op=-ne
if(~ $1 -eq -ne){
	op=$1
	shift
}
if(~ $1 -* || ~ $#* 0) {
	echo 'Usage: '$0' [-eq -ne] file...' >[1=2]
	exit usage
}

new=$(mktemp) || { echo "$0: Cannot create temporary file" >&2; exit 1;  }

# trap 'rm -f $new; exit 1' 1 2 15	# clean up files

cat >$new
for(i) {
	cmp -s $new $i
	
	switch($op^$status) {
	# differed but we wanted same
	case -eq*differ
		;
	# didn't differ but we wanted different
	case -ne
		;
	# got what we wanted or perhaps an error
	case *
		cp $new $i
	}
}
rm -f $new