THE LINUX VERSION OF ARDUINO

THE LINUX VERSION OF ARDUINO
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The LINUX version of arduino , is it capable of executing
LINUX commands like FORK() or THREADS?

Arrghh! My eyes!

It's Linux, not LINUX, Arduino not ARDUINO, fork not FORK, and threads not THREADS.

Is there a way to write parallel functions/statements in ARDUINO ide ?

What is a parallel function? Please explain.