As in all computers, a file system under Unix operating system has a tree-like structure. The highest directory in unix is / and there are at least several directories under it, such as etc/ and bin/ directories, as shown above. The " / " in names refer to directory, otherwise a file.

Actual user directory is beneath /home/, as denoted in the figure as the "user login level". So, if Nikita logs into this computer, he is actually at /home/nikita/ directory.