Since SIC was designed to be portable on various operating systems (currently VMS, Unix, Mac-OS, MS-Windows), interaction with the operating system is normally kept to a minimum.
However, many operations eventually deal with files handled by the operating system. To avoid platform dependencies, SIC allows some basic file operations through the SIC command.
When control is desired at the operating system level, the command SYSTEM can be used to access it without loosing the SIC context. For user convenience, SIC also accepts the short-cut
$ operating_system command
instead of the more conventional SIC-like syntax
SYSTEM "operating_system command"