1.命令功能
tail默认显示文件内容尾部10行。
2.语法格式
tail option file
参数说明
|
参数 |
参数说明 |
|
-n |
显示指定行数 |
|
-f |
实时输出文件变化后追加的数据 |
|
-s |
监视文件变化的间隔秒数 |
|
-v |
总是显示包含指定文件名的文件头 |
3.使用范例
范例1 tail 默认显示后10行
[root@localhost chu]# tail passwd nobody:x:99:99:Nobody:/:/sbin/nologin vcsa:x:69:69:virtual console memory owner:/dev:/sbin/nologin saslauth:x:499:76:Saslauthd user:/var/empty/saslauth:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin ntp:x:38:38::/etc/ntp:/sbin/nologin cxf:x:500:500::/home/cxf:/bin/bash ok:x:501:501::/home/ok:/bin/bash joe:x:502:502::/home/joe:/bin/bash chu:x:503:503::/home/chu:/bin/bash
范例2 实时监控文件变化追加的内容
[root@localhost chu]# tail -f /var/log/messages Apr 23 14:47:22 localhost sshd[1309]: Server listening on :: port 22. Apr 23 14:47:22 localhost xinetd[1320]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in. Apr 23 14:47:22 localhost xinetd[1320]: Started working: 1 available service Apr 23 14:47:24 localhost sshd[1436]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use. Apr 23 14:47:24 localhost sshd[1436]: error: Bind to port 22 on :: failed: Address already in use.
范例3 显示文件头部
[root@localhost chu]# tail -vf /var/log/messages ==> /var/log/messages <== Apr 23 14:47:22 localhost sshd[1309]: Server listening on :: port 22. Apr 23 14:47:22 localhost xinetd[1320]: xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in. Apr 23 14:47:22 localhost xinetd[1320]: Started working: 1 available service Apr 23 14:47:24 localhost sshd[1436]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use. Apr 23 14:47:24 localhost sshd[1436]: error: Bind to port 22 on :: failed: Address already in use.