Level Goal
The password for the next level is stored in the file data.txt, which contains base64 encoded data

Commands you may need to solve this level: grep, sort, uniq, strings, base64, tr, tar, gzip, bzip2, xxd

If we do an ‘ls -la’ we see that there is an file data.txt in the home directory. Lets see what kind of file this is.
file data.txt

It has an ASCII text that is base64 encoded as the goal of the level says. Lets see the manpage of base64.
man base64

Looking at the manpage we can decode it using the -d option.
base64 data.txt

It prints: The password is IFukwKGsFW8MOq3IRFqrxE1hxTNEbUPR
This is the password for level 11.