Unix OS

I like the "mkdir" command and I made an informatics directory. I have some other directories on my account that I did not how to remove them, but now I know I can use "rmdir". I also used the "ls" and "ls -la" commands to check the files in a directory. I used the "pwd" command to see where I was from the root. I can go back toward the root by keying "cd .." and it will take me back up the tree directory. I am not very knowledgeable of DOS commands, but after a few minutes on Google and some practice in MSDOS I found that the "cd .." does the same thing and alsoo "mkdir" adn "rmdir" do the same thing. I made an Informatics folder and then removed it from my hard drive with DOS. I use "dir" to list the files and folders in a directory instead of "ls", but other than that it pretty cool because I have only used DOS in the past to format my hard drive and prepare it for Windows.