说明
head命令用于显示文件内容头部，默认为文件的前10行。
格式
head [option] [filename]
常用参数说明
- -n：指定显示的行数
- -c：指定显示的字节数
- -q：不显示包含给定文件名的文件头
- -v：总是显示包含给定文件名的文件头
示例
1、不使用参数，只显示文件的前10行
[root@localhost ~]# head /etc/services
# /etc/services:
# $Id: services,v 1.55 2013/04/14 ovasik Exp $
#
# Network services, Internet style
# IANA services version: last updated 2013-04-10
#
# Note that it is presently the policy of IANA to assign a single well-known
# port number for both TCP and UDP; hence, most entries here have two entries
# even if the protocol doesn't support UDP operations.
# Updated from RFC 1700, ``Assigned Numbers'' (October 1994). Not all ports
2、指定-n参数，显示指定的前n行
[root@localhost ~]# head -3 /etc/services
# /etc/services:
# $Id: services,v 1.55 2013/04/14 ovasik Exp $
#
3、指定-c参数，显示指定的前n个字节
[root@localhost ~]# head -c 10 /etc/services
# /etc/ser
4、显示多个文件
[root@localhost ~]# head -n 1 /etc/passwd /etc/gshadow
==> /etc/passwd <== #这里是文件头
root:x:0:0:root:/root:/bin/bash
==> /etc/gshadow <==
root:::
5、指定-q参数，不显示文件的文件头，跟上一个例子对比看
[root@localhost ~]# head -qn 1 /etc/passwd /etc/gshadow
root:x:0:0:root:/root:/bin/bash
root:::
6、指定-v参数，显示文件的文件头
[root@localhost ~]# head -vn 5 /etc/services
==> /etc/services <==
# /etc/services:
# $Id: services,v 1.55 2013/04/14 ovasik Exp $
#
# Network services, Internet style
# IANA services version: last updated 2013-04-10