2.5. Filesystem Basics

Linux organizes its file in directories, where each directory can contain files or other directories.
There is one topmost directory which is called the root directory, and is labelled as /.
The . meta directory designated the current directory. ".." is the directory above it. If a / is prefixed at the beginning than the path would be absolute.
The cd command changes the current working directory to a different directory. The pwd command prints the path of the current working directory.
Here's an example session at the command line:

shlomi:~$ cd /usr
shlomi:/usr$ pwd
/usr
shlomi:/usr$ cd local/bin
shlomi:/usr/local/bin$ pwd
/usr/local/bin
shlomi:/usr/local/bin$ cd ../../share
shlomi:/usr/share$ pwd
/usr/share
shlomi:/usr/share$ cd /usr/share/doc/
shlomi:/usr/share/doc$ pwd
/usr/share/doc
shlomi:/usr/share/doc$ cd ./vim-X11-6.1/
shlomi:/usr/share/doc/vim-X11-6.1$ pwd
/usr/share/doc/vim-X11-6.1
shlomi:/usr/share/doc/vim-X11-6.1$ cd ..
shlomi:/usr/share/doc$ cd rsync-2.5.6/
shlomi:/usr/share/doc/rsync-2.5.6$ pwd
/usr/share/doc/rsync-2.5.6
shlomi:/usr/share/doc/rsync-2.5.6$