nl 数字线，在没发现nl之前，一直用脚本来实现。
# head wireless.h
/*
* This file define a set of standard wireless extensions
*
* Version : 20 17.2.06
*
* Authors : Jean Tourrilhes - HPL
* Copyright (c) 1997-2006 Jean Tourrilhes, All Rights Reserved.
*/#ifndef _LINUX_WIRELESS_H
# nl wireless.h | head
1 /*
2 * This file define a set of standard wireless extensions
3 *
4 * Version : 20 17.2.06
5 *
6 * Authors : Jean Tourrilhes - HPL
7 * Copyright (c) 1997-2006 Jean Tourrilhes, All Rights Reserved.
8 */9 #ifndef _LINUX_WIRELESS_H |