Getting Java Started

Question

Hi I just recently installed RedHat Enterprise Linux WS Version 3 for i386 and installed J2se 1.4.2 SDK. I go into the directory with my .java and .class files and javac HelloWorld.java and get the error: bash: javac: command not found
Now I just started using Linux today and have been writing java programs for only about 5 weeks since I just started this class. So I am totally lost on what to do so that Linux will run the compiler or apletviewer. If anyone could give me some help or point me to a site on how to set up linux so that it will refer back to the compiler when i try to use it in Terminal. Thanks
Chris

Answer 1

Above, $SHELL is a shell variable, or environment variable. The "environment" is a collection of name/value pairs that describe the environment you're working under. One of these environment variables is PATH, which tells the shell what directories to look in to execute the commands you give on the command-line shell.
So if you type:vi MyProg.java the "vi" is the command you want to execute and "MyProg.java" is an argument to vi; in this case it's the name of a file you want to edit. The shell reads this command line, determines that you want to run the "vi" program, then looks in each directory in its PATH to find a program named "vi". If it finds it, it executes it.
When you add new programs, sometimes you want to put them on the path. You must not remove the stuff that's already on your path, because if you do you won't be able to find some programs. So what you do is you append a new directory to the end of the path.