OverTheWire Bandit 12
The password for the next level is stored in the file data.txt, which is a hexdump of a file that has been repeatedly compressed. For this level it may be useful to create a directory under /tmp in which you can work using mkdir. For example: mkdir /tmp/myname123. Then copy the datafile using cp, and rename it using mv (read the manpages!)
The original file looks to be hex dump from the xxd utility. -r(everse) the process and write back to binary.
Use the file command to identify the type of file. Then use the matching compression tool to unpack it. And so forth.