Solutions 

1.	Practice with sleep and ps.

2.	$ sleep 300
	$ ps
	...
	$ kill PID 	(of the sleep)

3.	(sleep 10; echo `Time to go home!') &

	Try killing the sleep or the shell executing the subshell.

4.	$ rm bozzzo 2>errfile
	$ more errfile

	$ rm bozzzo 2>/dev/null    # Bit bucket

