Hi All,
Is there a software or command for ubuntu12.04 which tells the last access time of USB external HDDs/history of access time of ext HDDs. Because someone has deleted some files from the ext HDDs. So it would be appreciated if anyone could help me in this.
Thanks in advance for your kind help.

Do you mean the last time you plugged the usb HDD in or the last time you wrote to it?

If it is the former, I think you can check your dmesg (but I can't remeber if it is time stamped)

/var/log/dmesgwill will have entries of when you plugged your HDD, also a good place to look for the device name if you are not sure.

If you are looking for the last time you eddited a file then (well there are many ways):

for example...in the last hour:

find /path/to/mount -type f -mmin 60

A google search will give you results for a bunch of ways to do this. It can be mind boggling or overloading to see so many ways but it will help to chug through them.

Ken

Thanks kenneth_phough,
I am looking for only the last time(s) that the external HDD was plugged in to PC(Not only to my PC and it may be to any PC), and not only last time but looking for at least 5 last plugged in times.
There is no use of my system log files if the others are connected that HDD in their machine while I don't have access to their PC. Isn't it?
So is there a way to find out at least 5 last plugged in time?
Thanks for your kind help.

I don't think there is a way to find out if an external hard drive has been plugged into some other computer that you do not have access to read the system logs.

I think the best way would be to keep track of the modified dates for the files on the HDD to see if anyone touched them.
Maybe do:

then, after someone else uses your external drive or every day (whichever suits your need), do:

and see if there are any changes, like modified date and file size.

HTH, Ken