UNIX is an operating system which was first developed in the 1960s, and has been under constant development ever since. By operating system, we mean the suite of programs which make the computer work. It is a stable, multi-user, multi-tasking sys…

There are many different versions of UNIX, although they share common similarities. The most popular varieties of UNIX are Sun Solaris, GNU/Linux, and MacOS X. Here in the School, we use Solaris on our servers and workstations, and Fedora Linux …

The UNIX operating system is made up of three parts; the kernel, the shell and the programs. The kernel The kernel of UNIX is the hub of the operating system: it allocates time and memory to programs and handles the filestore and communications in r…

Everything in UNIX is either a file or a process. A process is an executing program identified by a unique PID (process identifier). A file is a collection of data. They are created by users using text editors, running compilers etc. Examples of fil…

All the files are grouped together in the directory structure. The file-system is arranged in a hierarchical structure, like an inverted tree. The top of the hierarchy is traditionally called root (written as a slash / ) In the diagram above, we see…

To open an UNIX terminal window, click on the "Terminal" icon from the drop-down menus. An UNIX Terminal window will then appear with a % prompt, waiting for you to start entering commands.

ls (list) When you first login, your current working directory is your home directory. Your home directory has the same name as your user-name, for example, ee91ab , and it is where your personal files and subdirectories are saved. To find out what …

mkdir (make directory) We will now make a subdirectory in your home directory to hold the files you will be creating and using in the course of this tutorial. To make a subdirectory called unixstuff in your current working directory type % mkdir uni…

cd (change directory) The command cd directory means change the current working directory to ' directory '. The current working directory may be thought of as the directory you are in, i.e. your current position in the file-system tree. To c…

Still in the unixstuff directory, type % ls -a As you can see, in the unixstuff directory (and in all other directories), there are two special directories called (.) and (..) The current directory (.) In UNIX, (.) means the current directory, so ty…

pwd (print working directory) Pathnames enable you to work out where you are in relation to the whole file-system. For example, to find out the absolute pathname of your home-directory, type cd to get back to your home-directory and then type % pwd …

Understanding pathnames First type cd to get back to your home-directory, then type % ls unixstuff to list the conents of your unixstuff directory. Now type % ls backups You will get a message like this - backups: No such file or directory The reaso…

Command Meaning ls list files and directories ls -a list all files and directories mkdir make a directory cd directory change to named directory cd change to home-directory …

cp (copy) cp file1 file2 is the command which makes a copy of file1 in the current working directory and calls it file2 What we are going to do now, is to take a file stored in an open access area of the file system, and use the cp command to copy …

mv (move) mv file1 file2 moves (or renames) file1 to file2 To move a file from one place to another, use the mv command. This has the effect of moving rather than copying the file, so you end up with only one file rather than two. It can also be us…

rm (remove), rmdir (remove directory) To delete (remove) a file, use the rm command. As an example, we are going to create a copy of the science.txt file then delete it. Inside your unixstuff directory, type % cp science.txt tempfile.txt % ls % rm …

clear (clear screen) Before you start the next section, you may like to clear the terminal window of the previous commands so the output of the following commands can be clearly understood. At the prompt, type % clear This will clear all text and le…

Simple searching using less Using less, you can search though a text file for a keyword (pattern). For example, to search through science.txt for the word ' science ', type % less science.txt then, still in less, type a forward slash [/] fo…

Command Meaning cp file1 file2 copy file1 and call it file2 mv file1 file2 move or rename file1 to file2 rm file remove a file rmdir directory remove a directory cat file display a fil…

Most processes initiated by UNIX commands write to the standard output (that is, they write to the terminal screen), and many take their input from the standard input (that is, they read it from the keyboard). There is also the standard error, where…