Common Linux commands-File Processing Command 4

 

Tail view the last few lines of the file

The tail command displays 10 lines at the end of the file on the screen. If more than one file is specified, add a file name title before each folder. If the file name is not specified or the file name is "-", the standard input is read.

-N: the last few lines of the output file

-F output additional data when the file grows

Ln-link is used to generate link files

Links are divided into hard links and soft links. Hard links are created by default.

-S: Create a soft link

We can see that we created a hard link test2 to test3 above. At this time, we updated test2 and test3. This is because hard links are physically the same file. Each file in Linux has an I node, which is unique. At this time, we create a hard link and test3 uses the same I node as test2. Because of this, these two files are also synchronously updated. Sometimes we need to back up data in the system, but each modification must replace the original data, which is too cumbersome, at this time, we can create a hard link and place it in different directories for Synchronous updates.

Soft links are equivalent to shortcuts in windows. Although this is not the case, we can understand it in this way.

Hard links cannot be cross-file systems. Soft links can be cross-file systems.

From: Meng xiangyue's column