In reply to:

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Once I've finished compiling do I have to type anything to get back the original state it was in before I issued the path command?

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You could, but I find it easier and safer to start one shell (in its own xterm if I'm using X, or on its own virtual console), set its environment up, use it for compiling, then simply quit it (using "exit") when I'm done. If you don't use a seperate terminal window or console, it's easiest to start a new sub-shell (by typing "bash", or your preferred shell's name), and leave it when you're done. The hard bit is remembering which shell you're leaving at which level.

I suppose one could "bash; echo Exited arm-linux-path shell" to get some feedback as to which level you have left when you type "exit"; it's not something I've tried myself.