#!/bin/rc switch($#*) { case 0 sed 10q case 1 if (~ $1 -[1-9]* ) { n = `{echo $1 | sed 's/-//'}; sed $n^q } if not { sed 10q < $1 } case 2 n = `{echo $1 | sed 's/-//'}; sed $n^q < $2 case * echo 'usage: head file' >[1=2] echo ' head -[number] file' >[1=2] }