When navigating the filesystem tree, changing your current directory is one of the basic actions.
In Unix, changing your current directory is accomplished by the cd command.
The cd command syntax is very simple: just specify the directory you’d like to navigate to. At any moment of your navigation, feel free to use the [pwd command][pwd-command] to confirm your current directory:
In this example, you can see how initially I was in my home directory, /home/greys, and then changed the directory to /etc.
In Unix and Unix-like operating systems, each directory contains two special entries:
Using the .. entry you can change to the parent directory (the one above your current directory), even without knowing the exact name of that parent directory.
If for some reason you can’t change the directory, an error message will be shown:
ubuntu$ cd /tmp/protected/ bash: cd: /tmp/protected/: Permission denied As you can probably tell from the error message, the problem is directory permissions. If we use the ls command to verify access permissions, we can see that in my example the /tmp/protected directory belongs to root, and only root can access it: