An Introduction to Programming with Unix

Here is an outline of the process you will follow to write a program:

1. Log in.
2. Use an editor (probably XEMACS) to create a file that contains your program. Later, you will also use the editor to make changes in the program.
3. Use a compiler to process your program so that the computer can execute it. For java programs, you use ``javac''.
4. To run your program, use ``java'', which is the interpreter for your compiled ``.class'' file.
5. Repeat the last three steps until your program works.
6. Log out by typing the command ``logout".

Here is an example of a complete programming session. $ ls *.java (see what C files I have.)
$ xemacs demo.java (create a new one.)
$ javac demo.java (try to compile it. A file ''demo.class'' will be created if successful.)
$ ls (see what files I have created.)
$ java demo (run your java program; note that there is no file extension her. You are actually running the ''demo.class'' bytecode.)
$ logout Notice that Unix types out a prompt (normally ``$") and expects you to type commands. These commands are normally English words or abbreviations of English words, followed by arguments. Here are some typical Unix commands: ls ( LiSt the files on your directory) Generally the Unix philosophy is to say as little as possible. If a command works, Unix just gives you another prompt. If something is wrong, you will get an error message. Please see section 7.3 for programming the system within EMACS.