#!/usr/bin/perl -n
# cat /etc/passwd | pipe-rx-count root
# root:x:0:0:root:/root:/bin/bash
# showing 1 of 57 lines
BEGIN{
	$pat=shift;
}

$n++;

/$pat/ && print && $m++;

END{
	warn "showing ", $m, " of ", $n, " line", ($n==1?"":"s"), "\n"
}