#!/usr/bin/awk -f
# ncomm-1565083172
BEGIN {
	if(ARGC<2) {
		print "usage: ncomm list_1 ... list_N" >"/dev/stderr"
		exit(1)
	}
	for(i=1;i<ARGC;i++) {
		print s ARGV[i]
		s=s"| "
		while((rc=getline < ARGV[i])>0) { P[$0]++ ; f[$0,i]++ }
		if(rc<0) {
			print "ncomm: read error in file: "ARGV[i] >"/dev/stderr"
			exit(2)
		}
	}
	print s
	c="sort | cut -d/ -f2-"
	for(i in P) {
		printf i"/" | c
		for(n=1;n<ARGC;n++) printf f[i,n]?"+ ":"· " | c
		print i | c
	}
	close(c)
}