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This article mainly introduces linux how to view the last few lines of the file, the article is very detailed, has a certain reference value, interested friends must read it!

Effect picture

Tail-n 20 filename

Description: displays the last 20 lines of filename.

How to use tail Command under Linux

The purpose of the linux tail command is to output the last part of the specified file to a standard device in accordance with the requirements, usually the terminal. Generally speaking, it is to display the last few lines of a file to the terminal. If the file is updated, tail will take the initiative to refresh itself to ensure that you see the latest contents of the file.

1. Tail command syntax

Tail [- f] [- c Number |-n Number |-m Number |-b Number |-k Number] [File]

Parameter explanation:

-f this parameter is used to monitor the growth of File files.

-c Number reads the specified file from the Number byte location

-n Number reads the specified file from the Number line location.

-m Number reads the specified file from the Number multi-byte character location, for example, your file assumes that it includes Chinese characters, and if you specify the-c parameter, it may cause truncation, but using-m will avoid the problem.

-b Number reads the specified file from the 512-byte block location represented by Number.

-k Number reads the specified file from the 1KB block location represented by Number.

File specifies the target file name of the operation

In all the above commands, number is involved. If it is not specified, 10 lines are displayed by default. The Number can be preceded by a plus or minus sign, indicating whether the offset is calculated from the top or the tail.

Tail runnable files are generally below / usr/bin/.

2. Demonstration example of how to use tail command

1. Tail-f filename

Note: monitor the tail content of the filename file (default 10 lines, equivalent to adding the parameter-n 10), refresh the display on the screen. Exit and press CTRL+C.

2. Tail-n 20 filename

Description: displays the last 20 lines of filename.

3. Tail-n + 20 filename

Description: displays the first 20 lines of filename.

4. Tail-r-n 10 filename

Description: display the last 10 lines of filename in reverse order.

Add:

Commands that are similar to tail functions include:

Cat displays the contents of the archive from the first line.

Tac displays the contents of the file from the last line.

More pagination displays the contents of the file.

Less is similar to more, but supports paging forward

Head shows only the first few lines

Tail shows only the next few lines

N display the contents of the file with a line number

Od displays the contents of the file in binary mode

1. View the text file header n lines

Head-n 200 filename #-200 can be replaced with any number

2. View the last n lines of the text file

Tail-n 200 filename #-200 can be replaced with any number

3. View the number of lines of the text file

Wc-l filename

Linux-Centos file to see how to display the last few lines, certain lines

1. Show the last 20 lines

Tail-n 20 filename

Such as tail-n 20 log.txt

two。 Show middle 20, starting at 1000

Cat log.txt | tail-n + 1000 | head-n 20

Note: tail-n + line number means to start with more or less lines, if it is tail-n-line = = tail-n line means how many lines at the end of the file

Data of the first 20 rows of head-n 20

3. You can also use the sed command

Such as sed-n '100120p' log.txt 100 to 120 rows of data.

These are all the contents of the article "how to view the next few lines of a file by linux". Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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