/dev/null is often referred to a black hole in Linux based systems. It discards all the data written to it and sends EOF (End of File) character to any process reading data from it. With this logic, we can clear the contents of a file
$ cat file.txt This file has some content. Let's use /dev/null to clear the file
Let’s clear the file contents
$ cat /dev/null > file.txt
As you can see we are directing the contents of /dev/null to the file.txt. As mentioned earlier, /dev/null is a blank file, size of which is 0. So by redirecting /dev/null to the file file.txt, Let’s confirm this
$ stat file.txt File: `file.txt' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: 801h/2049d Inode: 1004 Links: 1 ...
You can see more options to clear a file in Linux.