Logging Onto and Navigating the UNIX System

Logging On to the System

1. Once you have connected to the i4 machine, you will receive the prompt:

Enter your NetID at the login prompt, and press the <Return> key. Note that the system is case-sensitive and that your NetID should be entered in lower case — so, please make sure that the "caps lock" key on your keyboard is not depressed!

2. You will next receive the prompt

Enter your password. Your password is your NetID password. Note, the characters will not be echoed on the screen as you type them in. As before, press <Return> when you are finished. (Remember, when typing in your password, that the system is case-sensitive!)

If you have not entered the login information correctly, you will get the message "Login incorrect"; try reentering your NetID and password.

If you have correctly entered your NetID and password, you should be greeted with a sign-on message. After a few moments, the system prompt will appear.

Directories, Files, and Pathnames

You are always in a working directory. Your home directory is the working directory in which you find yourself when you log in.

The contents of a working directory may include files as well as other directories. When a directory contains other directories, it is often referred to as a parent, and the directories it contains are its children.

The arrangement (called a directory tree) is something like a family tree: each directory has a parent one level up from it in the tree. In the example below, homework is the parent of file5 and file6, and smithj is the parent of homework. The system's topmost directory (/) is called the root directory.

The pathname of a directory or file indicates its place in the directory tree, starting from the root of the tree. In our example, the pathname of file1 is /usr/smithj/file1, and the pathname of file6 is /usr/smithj/homework/file6. Note that, in the pathname, the directory levels are separated by slashes (/). The directory /usr contains the home directories of smithj and other users.

On UNIX systems running at NYU, file names and directory names may be up to 31 characters long. When you first receive your account, your home directory will contain a few files which have been placed there by the system manager so that your account will operate properly. Normally, in a new account, the home directory will contain no further directories, but at NYU, there will also be a directory called bin, which is a receptacle for your personal executables and shell programs. Commands that you can use to create your own files and directories are given in the next section.