AllNames returns all command-names for completion package.

CorrectCase corrects `path`'s case.

Exec is the entry function to call built-in functions from Shell.

stampIsOk returns true if year,month,mday,hour,min,sec isnot invalid.

BoolOptions are the all global option list.

ReadStdinAsFile is the flat to read commands from stdin as a file stream.

Param is the interface for built-in command.