I thought root was all-mighty... but it seems not.

I tried installing Jabberwocky, a Java IDE for Lisp. I tried installing it as a normal user but of course I couldn't write to /usr so I switched to root. I couldn't install.

bash-2.05b# ./install
Compiling Install.java
./install: line 3: javac: command not found
Compiling AbstractXMLConfig.java
./install: line 5: javac: command not found
Compiling XMLConfigArgument.java
./install: line 7: javac: command not found
Compiling XMLConfigClass.java
./install: line 9: javac: command not found
Compiling XMLConfigField.java
./install: line 11: javac: command not found
Compiling XMLConfigMethod.java
./install: line 13: javac: command not found
Compiling XMLConfigObject.java
./install: line 15: javac: command not found
Compiling XMLConfigReader.java
./install: line 17: javac: command not found
Compiling InterqctionCommqnds.java
./install: line 19: javac: command not found
Compiling Util.java
./install: line 21: javac: command not found
Start the install program
./install: line 24: java: command not found

But a normal COULD use javac without problem. What could be causing this ? Do different users have different PATH variables ?

of course. PATH is user-customizable. so, root's PATH doesn't include the path to java. see where java is by looking at PATH for the normal user. then modify root's PATH accordingly.

Did you log in as root or did you use su? Java is on the path if you installed it, but not when you su root.

what do you mean? even if java is not in PATH when you su, i'm quite sure that you can just do PATH=$PATH:<path to java> to add it, at least temporarily.

Okay, I'll check that when I get back home... just to be sure, was the way to change PATH was export PATH=$PATH:/path:... ?

Tried to post this morning but for some reason was not letting me.

Yes you could fairly easily. But if he is using su to get to root and not manually setting the path to javac then this may be the problem.
Remember his questions: "But a normal COULD use javac without problem. What could be causing this ? Do different users have different PATH variables ?" The fact that you get a different path in a shell as su from what you would get at a login shell answers these questions. I just wanted to clarify whether it was truly root's PATH settings that were borked or if he was using su.

As rgiggs said, chances are all you would need to do is "PATH=$PATH:/usr/lib/java/bin" or wherever you installed the JVM if you did not use the one that came with Slack 10.

Okay guys, indeed root and user did not have the same PATH. I added it to PATH temporarily and it did the job just fine. Thanks.