（八）资料撷取:head、tail

资料撷取:取出前面（head）与取出后面（tail）文字的功能

head（取出前几行）

写法：head [-n number] 档案

参数：   -n：后面接数字，代表显示几行的意思

1 [root@localhost ~]# head -n 5 /etc/man.config
2 #
3 # Generated automatically from man.conf.in by the
4 # configure script.
5 #
6 # man.conf from man-1.6f
7 [root@localhost ~]# 

tail（取出后面几行）

写法：tail [-n number] 档案

参数：   -n：后面接数字，代表显示几行的意思

1 [root@localhost ~]# tail -n 5 /etc/man.config
2 # /etc/cron.weekly/makewhatis.cron
3 # will not update makewhatis database.
4 # Otherwise the database will be updated.
5 # 
6 #MAKEWHATISDBUPDATES    n
7 [root@localhost ~]# 

如何取/etc/man.config文件的第11行到第20行？    head -n 20 /etc/man.config | tail -n 10

 1 [root@localhost ~]# head -n 20 /etc/man.config | tail -n 10
 2 # when MANPATH contains an empty substring), to find out where the cat
 3 # pages corresponding to given man pages should be stored,
 4 # and to map each PATH element to a manpath element.
 5 # It may also record the pathname of the man binary. [This is unused.]
 6 # The format is:
 7 #
 8 # MANBIN                pathname
 9 # MANPATH               manpath_element [corresponding_catdir]
10 # MANPATH_MAP           path_element    manpath_element
11 #
12 [root@localhost ~]#