How does Linux empty the contents of a file?

This article mainly explains "Linux how to clear the file content", the article explains the content is simple and clear, easy to learn and understand, the following please follow the editor's train of thought slowly in depth, together to study and learn "Linux how to empty the file content" bar!

1. Use the redirect method [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # > test.txt [root@centos7 ~] # du-h test.txt 0 test.txt2, use the true command to redirect the empty file [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # true > test.txt [root@centos7 ~] # du-h test.txt 0 test.txt3, Use the cat/cp/dd command and / dev/null device to clear the file [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # cat/ dev/null > test.txt [root@centos7 ~] # du-h test.txt 0 test.txt## # [root@centos7 ~] # echo "Hello World" > test.txt [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # cp / dev/null test.txt cp: is "test.txt" overwritten? Y [root@centos7 ~] # du-h test.txt 0 test.txt### [root@centos7 ~] # echo "Hello World" > test.txt [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # dd if=/dev / null of=test.txt recorded 0's read in and 0's write out 0 bytes (0 B) has been copied 0.000266781 seconds, 0.0 kB/ seconds [root@centos7 ~] # du-h test.txt 0 test.txt4, use the echo command to clear the file [root@centos7 ~] # echo "Hello World" > test.txt [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # echo-n "> test.txt = > to add the"-n "parameter, which is"\ n "by default. That is, the carriage return character [root@centos7 ~] # du-h test.txt 0 test.txt5, use the truncate command to clear the file [root@centos7 ~] # du-h test.txt 4.0K test.txt [root@centos7 ~] # truncate-s 0 test.txt-s parameter to set the size of the file, empty the file, set it to 0 [root@centos7 ~] # du-h test.txt 0 test.txt thank you for reading, the above is the content of "Linux how to clear the contents of the file", after the study of this article, I believe you have a deeper understanding of how Linux empties the contents of the file, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!