Returns a character string showing the mode in which a process
    is executing. The F$MODE function has no arguments, but must be
    followed by parentheses.

    Format

      F$MODE()

1  –  Return Value

    The character string INTERACTIVE for interactive processes.
    If the process is noninteractive, the character string BATCH,
    NETWORK, or OTHER is returned. Note that the return string always
    contains uppercase letters.

2  –  Example

  $ IF F$MODE() .NES. "INTERACTIVE" THEN GOTO NON_INT_DEF
  $ INTDEF:         ! Commands for interactive terminal sessions
     .
     .
     .
  $ EXIT
  $ NON_INT_DEF:         !Commands for noninteractive processes
     .
     .
     .

      This example shows the beginning of a login.com file that has
      two sets of initialization commands: one for interactive mode
      and one for noninteractive mode (including batch and network
      jobs). The IF command compares the character string returned
      by F$MODE with the character string INTERACTIVE; if they are
      not equal, control branches to the label NON_INT_DEF. If the
      character strings are equal, the statements following the
      label INTDEF are executed and the procedure exits before the
      statements at NON_INT_DEF.