Moving a file inside the same File System

Question

I am trying to understand what it happens to a file when I move it from a directory to another, inside the same File System.

Here is the example I made up.

I have two directories and a file :

• ~/Documents/dir1
• ~/Documents/dir2
• ~/Documents/dir1/fileName.txt

Here I have some details about the file fileName.txt (ls -li):

784088 -rw-r--r-- 1 myUser myUser 0 Oct 25 02:18 fileName.txt

Then, I moved the file fileName.txt from dir1 to dir2 by issuing the following command:

~/Documents/dir1$ mv fileName.txt ../dir2

and here I have the details about the file fileName.txt (ls -li) after having issued mv:

784088 -rw-r--r-- 1 myUser myUser 0 Oct 25 02:22 fileName.txt

What I expected was a change of inode number, but I was wrong . So, for what I have understood up to now, by moving a file inside the same File System:

• the data block is not touched (that's good to me)
• the inode (that is strange to me)

Can anyone tell me then what it changes in file properties (apart from modification time)?

Thank you in advance, really.

Answer 1

Within the same filesystem, mv-ing actually uses rename(2). So the inode will remain intact, just the inode is removed from one directory entry and attached to another.