(octave.info)Paging Screen Output

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14.1.1.1 Paging Screen Output
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When running interactively, Octave normally sends all output directly to
the Command Window.  However, when using the CLI version of Octave this
can create a problem because large volumes of data will stream by before
you can read them.  In such cases, it is better to use a paging program
such as ‘less’ or ‘more’ which displays just one screenful at a time.
With ‘less’ (and some versions of ‘more’) you can also scan forward and
backward, and search for specific items.  The pager is enabled by the
command ‘more on’.

   Normally, no output is displayed by the pager until just before
Octave is ready to print the top level prompt, or read from the standard
input (for example, by using the ‘fscanf’ or ‘scanf’ functions).  This
means that there may be some delay before any output appears on your
screen if you have asked Octave to perform a significant amount of work
with a single command statement.  The function ‘fflush’ may be used to
force output to be sent to the pager (or any other stream) immediately.

   You can select the program to run as the pager with the ‘PAGER’
function, and configure the pager itself with the ‘PAGER_FLAGS’
function.

 -- : more
 -- : more on
 -- : more off
     Turn output pagination on or off.

     Without an argument, ‘more’ toggles the current state.

     The current state can be determined via ‘page_screen_output’.

     See also: Note: page_screen_output, Note:
     page_output_immediately, *note PAGER:
     XREFPAGER, Note: PAGER_FLAGS.

 -- : VAL = PAGER ()
 -- : OLD_VAL = PAGER (NEW_VAL)
 -- : PAGER (NEW_VAL, "local")
     Query or set the internal variable that specifies the program to
     use to display terminal output on your system.

     The default value is normally "less", "more", or "pg", depending on
     what programs are installed on your system.  Note: Installation.

     When called from inside a function with the "local" option, the
     variable is changed locally for the function and any subroutines it
     calls.  The original variable value is restored when exiting the
     function.

     See also: Note: PAGER_FLAGS, Note:
     page_output_immediately, *note more:
     XREFmore, Note: page_screen_output.

 -- : VAL = PAGER_FLAGS ()
 -- : OLD_VAL = PAGER_FLAGS (NEW_VAL)
 -- : PAGER_FLAGS (NEW_VAL, "local")
     Query or set the internal variable that specifies the options to
     pass to the pager.

     When called from inside a function with the "local" option, the
     variable is changed locally for the function and any subroutines it
     calls.  The original variable value is restored when exiting the
     function.

     See also: Note: PAGER, Note: more, Note:
     page_screen_output, Note:
     page_output_immediately.

 -- : VAL = page_screen_output ()
 -- : OLD_VAL = page_screen_output (NEW_VAL)
 -- : page_screen_output (NEW_VAL, "local")
     Query or set the internal variable that controls whether output
     intended for the terminal window that is longer than one page is
     sent through a pager.

     This allows you to view one screenful at a time.  Some pagers (such
     as ‘less’—see Note: Installation) are also capable of moving
     backward on the output.

     When called from inside a function with the "local" option, the
     variable is changed locally for the function and any subroutines it
     calls.  The original variable value is restored when exiting the
     function.

     See also: Note: more, *note page_output_immediately:
     XREFpage_output_immediately, Note: PAGER, Note:
     PAGER_FLAGS.

 -- : VAL = page_output_immediately ()
 -- : OLD_VAL = page_output_immediately (NEW_VAL)
 -- : page_output_immediately (NEW_VAL, "local")
     Query or set the internal variable that controls whether Octave
     sends output to the pager as soon as it is available.

     Otherwise, Octave buffers its output and waits until just before
     the prompt is printed to flush it to the pager.

     When called from inside a function with the "local" option, the
     variable is changed locally for the function and any subroutines it
     calls.  The original variable value is restored when exiting the
     function.

     See also: Note: page_screen_output, Note:
     more, Note: PAGER, *note PAGER_FLAGS:
     XREFPAGER_FLAGS.

 -- : fflush (FID)
     Flush output to file descriptor FID.

     ‘fflush’ returns 0 on success and an OS dependent error value (−1
     on Unix) on error.

     Programming Note: Flushing is useful for ensuring that all pending
     output makes it to the screen before some other event occurs.  For
     example, it is always a good idea to flush the standard output
     stream before calling ‘input’.

     See also: Note: fopen, Note: fclose.