One Linux command per day (1): Tail command

The tail command writes the file to standard output starting at the specified point. Using the-f option of the tail command makes it easy to see the log files that are being changed, TAIL-F filename will display the most up-to-date contents of the filename on the screen, and not only refresh, so you can view the latest file content.

1. command format;

tail[necessary parameters [selection parameters] [file]

2. Command function:

Used to display the content at the end of the specified file, and is processed as input when the file is not specified. Common view log files.

3. Command parameters:

-F Loop Read

-Q does not display processing information

-V displays detailed processing information

Number of-c< > bytes displayed

-n< lines > Display rows

--pid=pid is shared with-F, which means that the process ends after the id,pid dies.

-Q,--quiet,--silent never output the header of the file name

-S,--sleep-interval=s is combined with-F, which means sleep s seconds at each repetition interval

4. Usage examples:

Example 1: Displaying the end of a file

Command:

5 Log2014.log

Output:

5------12 ==============================[[email protected] test]#

Description

Displays the last 5 lines of the file

Example 2: Looping through the contents of a file

Command:

Tail-f Test.log

Output:

[[email protected] ~]# Ping192.168.120.204> Test.log &[1]11891[Email protected] ~]# tail-F test.log PING192.168.120.204(192.168.120.204) About( -) bytes of data. -bytes from 192.168.120.204: icmp_seq=1Ttl= -Time=0.038Ms -bytes from 192.168.120.204: icmp_seq=2Ttl= -Time=0.036Ms -bytes from 192.168.120.204: icmp_seq=3Ttl= -Time=0.033Ms -bytes from 192.168.120.204: icmp_seq=4Ttl= -Time=0.027Ms -bytes from 192.168.120.204: icmp_seq=5Ttl= -Time=0.032Ms -bytes from 192.168.120.204: icmp_seq=6Ttl= -Time=0.026Ms -bytes from 192.168.120.204: icmp_seq=7Ttl= -Time=0.030Ms -bytes from 192.168.120.204: icmp_seq=8Ttl= -Time=0.029Ms -bytes from 192.168.120.204: icmp_seq=9Ttl= -Time=0.044Ms -bytes from 192.168.120.204: icmp_seq=TenTtl= -Time=0.033Ms -bytes from 192.168.120.204: icmp_seq= OneTtl= -Time=0.027MS [[email protected]~]#

Description

Ping 192.168.120.204 > Test.log &//Ping remote host in background. and output files to Test.log; This practice also allows for more than one file to monitor. Use CTRL + C to terminate.

Example 3: Displaying a file starting from line 5th

Command:

Tail-n +5 log2014.log

Output:

[email protected] test]# cat Log2014.log the- on the- Geneva the-Geneva the-Geneva the- to the- . the- - the- , the- the the-Ten the- One the- A==============================[email protected] test]# tail-N +5Log2014.log the- to the- . the- - the- , the- the the-Ten the- One the- A==============================

One Linux command per day (1): Tail command