Gives access to the operating system command line environment
    from within SQL.

    The dollar sign ($)  tells SQL to spawn a subprocess and pass the
    rest of the line to the operating system for processing. You must
    follow the dollar sign with an operating system command. After
    the operating system processes the command, it logs out of the
    subprocess process and returns control to SQL.

1  –  Environment

    You can invoke operating system commands only in interactive SQL.

2  –  Format

  $ operating-system-command

3  –  Arguments

3.1  –  operating-system-command

    Specifies a valid operating system command.

4  –  Examples

    Example 1: Using the DCL DIRECTORY command from within SQL

    SQL> $ DIRECTORY *.SQL

    Directory DISK2:[DEPT3.ACCT]

    DEFPRO.SQL;6    NOTEQUAL.SQL;1   QUERY.SQL;1    REFEXAM.SQL;12
    STORE.SQL;1     UPDATE.SQL;2

    Total of 6 files.
    SQL>