The os package
The os packages contains various modules pertaining to Operating System functionality such as:
Concurrency
Process, to launch child processes
JobPool, to easily control a pool of child processes
[Coro](coro, which provides a basic coroutine implementation
I/O
Terminal, used to control terminal text output (color, etc.)
Pipe, to open, read from, and write to pipes
Dynlib, which deals with dynamic library loading
mmap, which exposes memory mapping capabilities
Channel, which implements channels
System
System, to get information such as the number of processors, the hostname, etc.
Env, to deal with environment variables
ShellUtils, used mostly to find executables
Time, to get the current time and date, and sleep