A partition copied with cat can't be mounted Well some days ago my mac got broken, I had an Ubuntu on it and booted through it, first thing I did I copied mac partition to an external hard partition, something like this:

cat /dev/sda2 &gt; /dev/sdc2


I was able to mount the sda2 partition in Ubuntu with hfsprogs, but I wasn't able to mount /dev/sdc2, I made a diff on two devices (with cmp) and they were just identical, now I erase sda2 and installed Yosemite again but I can't mount sdc2 even on mac (here it's disk2s2).

When I try to mount, verify or repair it, I get this error:

Invalid node structure


(this is the same error I got in Ubuntu for this partition), it's really weird cause I'm sure this partition is identical to the real one (and I was able to mount the real one in Ubuntu) I tried fixing it with DiskWarrior 5, it did its job without any error, but it didn't fix it.
cat is not an appropriate tool for copying volumes. It dumps files character by character. Yes, unix abstracts everything to a file, but it also distinguishes between character devices (files) and block devices (storage).

Wipe the partition and use dd, rsync, or a GUI tool like Carbon Copy Cloner to make a duplicate.

However, if I read your sequence correctly it looks like you made a copy and then wiped the original without verifying your copy. If so, time to get the backups out.