Builtin utilities

All builtin utilities self-document with the -h option.

Command	Function
`cd`	Change working directory. Optionally, change disk.
`chcp`	Change code page. (Not implemented.)
`chdir`	A synonym for `cd`.
`cls`	Clear the screen.
`dirs`	Print the directory stack.
`echo`	Echo arguments to stdout.
`eval`	Defer parsing of the word list until the evaluation phase.
`hashstat`	Print path hash statistics.
`heapstat`	Print heap usage statistics.
`history`	Display the history list.
`kill`	Kill background activity.
`popd`	Pop directory stack.
`ps`	List process and thread status.
`pushd`	Push a new current directory on the directory stack or exchange the top two items.
`rehash`	Rehash the path directories.
`rotd`	Rotate the directory stack.
`sleep`	Sleep for a specified period.
`source`	Read commands from a file.
`unhash`	Turn off path list hashing.
`verify`	Turn on write verification mode.
`wait`	Wait for children to complete.

Hamilton C shell, as it first wakes up.

A first few commands.

You can set the screen colors to your taste.