Ubuntu system corrupted

[Nils Kassube]

Hari wrote:
>   I have a dual boot - Ubuntu and windows 7. I recently wass playing
> around in the ubuntu and used the 'dd' command and it kinda corrupted
> my linux file system. I exactly dont know what happened to Linux now.
> All my data is missing. I did the boot-repair and now the grub is
> removed and it is directly booting to windows. Please help me recover
> all my data in ubuntu. It is very important. Please help me with the
> process. I am desperate!!
> 
> Here is the pastebin link containing the logs.
> 
> paste.ubuntu.com/11395840/

| sda6:
...
| Mounting failed:   mount: unknown filesystem type ''

To me it looks like your Ubuntu system was on /dev/sda6 (the other 
partitions seem to be OK). With your dd command you overwrote vital 
parts of that partition. IMHO it would be best to try to recover 
remaining data using photorec / testdisk (unless you have a backup of 
your valuable data). Then you would reinstall the system from scratch. 
But please wait for other opinions before you proceed.


Nils