How to know File creation time in Linux ?

In Linux or any Unix flavors, file-creation time isn't maintained. It will get change when the file-content changes. I tested and confirmed this 1.5 years before and shared my test results in this post.
http://ashok-linux-tips.blogspot.com/2010/11/finding-file-creation-time-in-linux.html

Now the good news is, with 'EXT4' file-system it is possible to get the File-creation time.

Here's the test results performed on a EXT4 file-system:

root@Linux-Mach # df -h
Filesystem            Size    Used   Avail   Use% Mounted on
/dev/sda2             3.8G  2.2G    1.4G   62%   /
/dev/sda3             4.6G  139M  4.3G    4%     /home
/dev/sda1              46M   11M   33M   25%   /boot
tmpfs                   333M     0      333M  0%    /dev/shm
root@Linux-Mach # cd /opt
root@Linux-Mach # touch sample_file
root@Linux-Mach # ls -l sample_file
-rw-r--r-- 1 root root 0 2012-04-24 18:35 sample_file                    # File-creation time is 18:35

root@Linux-Mach # date
Tue Apr 24 18:40:12 CDT 2012
root@Linux-Mach # cat > sample_file           
This is test file to check creation time of this file.
Ctrl+D
root@Linux-Mach # ls -l sample_file  
-rw-r--r-- 1 root root 29 2012-04-24 18:40 sample_file
root@Linux-Mach # ls -i sample_file  
135528 sample_file                                                                    # inode number  
root@Linux-Mach # debugfs -R 'stat <135528>' /dev/sda2          
Inode 14552801   Type regular    Mode  0644   Flags 0x80000
Generation 340511001    Version 0x0000000000000001
User  1000   Group  1000   Size 29 
File ACL 0    Directory ACL 0 
Links 1   Blockcount 8 
Fragment  Address 0    Number 0    Size 0
 ctime 0x3f1da5b513cbff4 -- Tue Apr 24 18:40:51 2012
 atime 0x3f1da5ec8725434 -- Tue Apr 24 18:40:54 2012
 mtime 0x3f1da5b513cbff4 -- Tue Apr 24 18:40:51 2012
crtime 0x3f1cacc966104fc -- Tue Apr 24 18:35:28 2012             # we could see file creation time    
Size of extra inode fields 28
EXTENTS
(0) 44665199
debugfs 1.41.11 (14-Mar-2010)

root@Linux-Mach #

Please note the entry "crtime"  which displays the file-creation time. In my view, this information would be of great help in certain situations.

Finding file creation time in Linux

Question:  In Linux, is it possible to find the actual time when a file was created first?

The Answer is NO until Ext3. 

File creation time ISN’T maintained in Linux with file-system Ext3 or earlier version. 
It will change when file content changes. It is explained with an example here:

[adevaraju@cac1-t1 ~]$ date

Tue Nov  9 01:22:25 CST 2010                                                      # Time now is 01:22:25

[adevaraju@cac01-t1 ~]$ echo "Some text on the file " > testfile       # Creating a file

[adevaraju@cac01-t1 ~]$ ls -lc testfile

-rw-r--r-- 1 adevaraju domain users 23 Nov  9 01:22 testfile     # Shows file change time as 01:22

 [adevaraju@cac01-t1 ~]$ ls -lu testfile

-rw-r--r-- 1 adevaraju domain users 23 Nov  9 01:22 testfile     # Access time is also 01:22

[adevaraju@cac01-t1 ~]$ cat testfile                                       # Now am accessing the file

Some text on the file

 [adevaraju@cac01-t1 ~]$ ls -lc testfile                            

-rw-r--r-- 1 adevaraju domain users 23 Nov  9 01:22 testfile     # Change time remains the same

[adevaraju@cac01-t1 ~]$ ls -lu testfile

-rw-r--r-- 1 adevaraju domain users 23 Nov  9 01:23 testfile     # Access time changed to 01:23

[adevaraju@cac01-t1 ~]$ date

Tue Nov  9 01:23:32 CST 2010

[adevaraju@cac01-t1 ~]$ echo "Additional text to the file" >> testfile # file content changed

 [adevaraju@cac01-t1 ~]$ ls -lc testfile                                                                            

-rw-r--r-- 1 adevaraju domain users 51 Nov  9 01:24 testfile      # Change time changes to 01:24

[adevaraju@cacllm01-t1 ~]$ ls -lu testfile

-rw-r--r-- 1 adevaraju domain users 51 Nov  9 01:23 testfile      # But access time remains the same since we did only changes to file.

[adevaraju@cacllm01-t1 ~]$ date

Tue Nov  9 01:24:22 CST 2010

[adevaraju@cacllm01-t1 ~]$

Atlast the original file creation time (which is 01:22) is gone, we CAN’T retrieve that information.

PS:  EXT4 file-system comes out with a feature to find the File-creation time. 

It is explained in this post:  http://ashok-linux-tips.blogspot.com/2012/04/how-to-get-file-creation-time-in-linux.html