Linux命令(94)之tail

linux命令之tail

1.tail介绍

linux命令tail用来查看文件的最后N行内容，默认tail查看最后10行内容

2.tail用法

tail [参数] 文件

3.实例

3.1.显示文件的最后5行内容

命令：

tail -n 5 a.txt

[root@centos79-3 ~]# tail -n 5 a.txt
8
9
10
11
12
[root@centos79-3 ~]# 

3.2.显示a.txt/b.txt文件的最后5行内容

[root@centos79-3 ~]# tail -q -n 5 a.txt b.txt
8
9
10
11
12
8
9
10
11
12
[root@centos79-3 ~]# 

3.3.显示a.txt/b.txt文件的最后5行内容，并显示分开文件名

命令：

tail -v -n 5 a.txt b.txt

[root@centos79-3 ~]# tail -v -n 5 a.txt b.txt
==> a.txt <==
8
9
10
11
12
 
==> b.txt <==
8
9
10
11
12
[root@centos79-3 ~]# 

3.4.实时读取/var/log/messages文件内容

命令：

tail -f /var/log/messages

[root@centos79-3 ~]# tail -f /var/log/messages
Sep 19 10:05:19 centos79-3 NetworkManager[710]: <info>  [1695089119.0694] dhcp4 (ens32):   nameserver '192.168.10.2'
Sep 19 10:05:19 centos79-3 NetworkManager[710]: <info>  [1695089119.0694] dhcp4 (ens32):   domain name 'localdomain'
Sep 19 10:05:19 centos79-3 NetworkManager[710]: <info>  [1695089119.0694] dhcp4 (ens32): state changed bound -> bound
Sep 19 10:05:19 centos79-3 dbus[708]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service'
Sep 19 10:05:19 centos79-3 systemd: Starting Network Manager Script Dispatcher Service...
Sep 19 10:05:19 centos79-3 dhclient[806]: bound to 192.168.10.225 -- renewal in 855 seconds.
Sep 19 10:05:19 centos79-3 dbus[708]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Sep 19 10:05:19 centos79-3 systemd: Started Network Manager Script Dispatcher Service.
Sep 19 10:05:19 centos79-3 nm-dispatcher: req:1 'dhcp4-change' [ens32]: new request (2 scripts)
Sep 19 10:05:19 centos79-3 nm-dispatcher: req:1 'dhcp4-change' [ens32]: start running ordered scripts...