Linux Base command (Tail command)

The tail command writes the file to the standard output from the specified point. Using the-f option of the tail command makes it easy to refer to the changing log file, Tail-f filename will display the tail contents of the filename on the screen, and not only refresh, so that you see the latest file content.

1. command format;

tail[necessary parameters [select parameters] [file]

2. Command function:

Used to display the content at the end of a specified file and to process it as input when no file is specified. Common view log files.

3. Command parameters:

-F Loop Read

-Q does not display processing information

-V Display detailed processing information

Number of-c< > bytes displayed

-n< number of rows > show rows

--pid=pid is shared with-F, which ends after the process id,pid dead.

-Q,--quiet,--silent never output the header of the filename

-S,--sleep-interval=s is shared with-F, which means sleeping s seconds at each repeated interval

4. Use instance:

Example 1: Display the end of a file

Command:

Tail-n 5 Log2014.log

Output:

[Root@localhost test]# tail-n 5 Log2014.log

2014-09

2014-10

2014-11

2014-12

==============================[root@localhost test]#

Description

Display the last 5 lines of the file

Example 2: Looping through the contents of a file

Command

Tail-f Test.log

Output:

[root@localhost ~]# ping 192.168.120.204 > Test.log &

[1] 11891 [root@localhost ~]# tail-f Test.log

PING 192.168.120.204 (192.168.120.204) bytes of data.

Bytes from 192.168.120.204:icmp_seq=1 ttl=64 time=0.038 ms

Bytes from 192.168.120.204:icmp_seq=2 ttl=64 time=0.036 ms

Bytes from 192.168.120.204:icmp_seq=3 ttl=64 time=0.033 ms

Bytes from 192.168.120.204:icmp_seq=4 ttl=64 time=0.027 ms

Bytes from 192.168.120.204:icmp_seq=5 ttl=64 time=0.032 ms

Bytes from 192.168.120.204:icmp_seq=6 ttl=64 time=0.026 ms

Bytes from 192.168.120.204:icmp_seq=7 ttl=64 time=0.030 ms

Bytes from 192.168.120.204:icmp_seq=8 ttl=64 time=0.029 ms

Bytes from 192.168.120.204:icmp_seq=9 ttl=64 time=0.044 ms

Bytes from 192.168.120.204:icmp_seq=10 ttl=64 time=0.033 ms

Bytes from 192.168.120.204:icmp_seq=11 ttl=64 time=0.027 ms

[Root@localhost ~]#

Description

Ping 192.168.120.204 > Test.log &//Ping the remote host in the background. and output files to Test.log; this practice is also used for more than one file monitoring. Use CTRL + C to terminate.

Example 3: Displaying files starting at line 5th

Command:

Tail-n +5 Log2014.log

Output:

[Root@localhost test]# Cat Log2014.log

2014-01

2014-02

2014-03

2014-04

2014-05

2014-06

2014-07

2014-08

2014-09

2014-10

2014-11

2014-12

==============================

[Root@localhost test]# tail-n +5 log2014.log

2014-05

2014-06

2014-07

2014-08

2014-09

2014-10

2014-11

2014-12

==============================

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