Inode number of the particular file gets changed.

[pankaj]

  *** SORRY FOR MY BAD ENGLISH ***

*** I was doing my daily exercise on the topic of timestamps.

        --> How the timestamps of the particular file gets changed, when we do some changes in that particular file.

        1)--> ex:- cat
              Access time is changed.

        2)--> ex:- vi
                   If some modification is made in that particular file with the help of vi editor.
                   then how the access,modification,change time of the particular gets changed.

        3)--> ex:- chmod
                   If we do chmod to a particular file only the change time of that file gets changed.

        4)-->ex:- touch
           If we touch a file, then all the timestamp get changed.

       *** I was using stat tool to check all the timestamps ***

                                               *************************************************************************************************
       HERE IS THE PROBLEM WHICH I AM FACING EVERYTIME,WHEN I DO STAT TO THAT PARTICULAR FILE.
                                               *************************************************************************************************
--> The inode number of that file gets changed, as I do any modification to that file.

tux@ubuntu:~/pankaj$ uname -r
3.11.0-15-generic

tux@ubuntu:~/pankaj$ cat /etc/issue
Ubuntu 12.04.4 LTS \n \l

tux@ubuntu:~/pankaj$ touch test
tux@ubuntu:~/pankaj$ ls
test
tux@ubuntu:~/pankaj$ stat test
  File: `test'
  Size: 0 Blocks: 0 IO Block: 4096 regular empty file
Device: 801h/2049d Inode: 56640 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/ tux) Gid: ( 1000/ tux)
Access: 2015-03-27 11:40:26.926255729 +0530
Modify: 2015-03-27 11:40:26.926255729 +0530
Change: 2015-03-27 11:40:26.926255729 +0530
 Birth: -

tux@ubuntu:~/pankaj$ cat test
hello world

tux@ubuntu:~/pankaj$ stat test
  File: `test'
  Size: 12 Blocks: 8 IO Block: 4096 regular file
Device: 801h/2049d Inode: 56643 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/ tux) Gid: ( 1000/ tux)
Access: 2015-03-27 11:43:48.011048224 +0530
Modify: 2015-03-27 11:43:48.011048224 +0530
Change: 2015-03-27 11:43:48.783020869 +0530
 Birth: -

tux@ubuntu:~/pankaj$ cat test
hello world hello world
_____________________________________________________________________________

*** No changes made now in it, then the inode remains same.

tux@ubuntu:~/pankaj$ stat test
  File: `test'
  Size: 12 Blocks: 8 IO Block: 4096 regular file
Device: 801h/2049d Inode: 56643 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/ tux) Gid: ( 1000/ tux)
Access: 2015-03-27 11:43:48.011048224 +0530
Modify: 2015-03-27 11:43:48.011048224 +0530
Change: 2015-03-27 11:43:48.783020869 +0530
 Birth: -
tux@ubuntu:~/pankaj$

*************************************************************************************************

-> When I touched file named test & did stat on that file, the inode number was 56640.
-> But as I edit the same file and add something to it, its inode number changed again to 56643.
-> Inode number should not change. then how come it gets changed !!!