head命令用于从文件的开头处显示指定数量的行。该命令默认显示文件的前10行。
命令格式：
head [OPTION]… [FILE]…
选项：
-n, –lines=K 显示K行
-c, –bytes=K 显示K字节
-q, –quiet 不显示文件名
-v, –verbose 显示文件名
-z, –zero-terminated 以NUL字符结尾
DESCRIPTION
Print the first 10 lines of each FILE to standard output. With more than one FILE, precede each with a header
giving the file name.
With no FILE, or when FILE is -, read standard input.
Mandatory arguments to long options are mandatory for short options too.
-c, --bytes=[-]NUM
print the first NUM bytes of each file; with the leading '-', print all but the last NUM bytes of each
file
-n, --lines=[-]NUM
print the first NUM lines instead of the first 10; with the leading '-', print all but the last NUM
lines of each file
-q, --quiet, --silent
never print headers giving file names
-v, --verbose
always print headers giving file names
-z, --zero-terminated
line delimiter is NUL, not newline
--help display this help and exit
--version
output version information and exit
NUM may have a multiplier suffix: b 512, kB 1000, K 1024, MB 1000*1000, M 1024*1024, GB 1000*1000*1000, G
1024*1024*1024, and so on for T, P, E, Z, Y.例1，查看文件开头，按照默认行数查看
study@DESKTOP:/var/log$ head dpkg.log
2022-03-24 21:47:25 startup packages remove
2022-03-24 21:47:25 status installed linux-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 remove linux-virtual:amd64 5.4.0.105.109 <none>
2022-03-24 21:47:25 status half-configured linux-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 status half-installed linux-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 status config-files linux-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 status not-installed linux-virtual:amd64 <none>
2022-03-24 21:47:25 status installed linux-headers-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 remove linux-headers-virtual:amd64 5.4.0.105.109 <none>
2022-03-24 21:47:25 status half-configured linux-headers-virtual:amd64 5.4.0.105.109
例2，查看文件开头，按照指定行数查看
study@DESKTOP:/var/log$ head -5 dpkg.log
2022-03-24 21:47:25 startup packages remove
2022-03-24 21:47:25 status installed linux-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 remove linux-virtual:amd64 5.4.0.105.109 <none>
2022-03-24 21:47:25 status half-configured linux-virtual:amd64 5.4.0.105.109
2022-03-24 21:47:25 status half-installed linux-virtual:amd64 5.4.0.105.109