Octave normally keeps track of the commands you type so that you can
recall previous commands to edit or execute them again. When you exit
Octave, the most recent commands you have typed, up to the number
specified by the variable history_size, are saved in a file.
When Octave starts, it loads an initial list of commands from the file
named by the variable history_file.
Here are the commands for simple browsing and searching the history list.
Accept the current line regardless of where the cursor is. If the line is non-empty, add it to the history list. If the line was a history line, then restore the history line to its original state.
Move ‘up’ through the history list.
Move ‘down’ through the history list.
Move to the first line in the history.
Move to the end of the input history, i.e., the line you are entering!
Search backward starting at the current line and moving ‘up’ through the history as necessary. This is an incremental search.
Search forward starting at the current line and moving ‘down’ through the history as necessary.
On most terminals, you can also use the up and down arrow keys in place of C-p and C-n to move through the history list.
In addition to the keyboard commands for moving through the history list, Octave provides three functions for viewing, editing, and re-running chunks of commands from the history list.
opt1 … ¶H = history () ¶H = history (opt1, …) ¶If invoked with no arguments, history displays a list of commands
that you have executed.
Valid options are:
n-nDisplay only the most recent n lines of history.
-cClear the history list.
-qDon’t number the displayed lines of history. This is useful for cutting and pasting commands using the X Window System.
-r fileRead the file file, appending its contents to the current history list. If the name is omitted, use the default history file (normally ~/.octave_hist).
-w fileWrite the current history to the file file. If the name is omitted, use the default history file (normally ~/.octave_hist).
For example, to display the five most recent commands that you have typed without displaying line numbers, use the command history -q 5.
If invoked with a single output argument, the history will be saved to that argument as a cell string and will not be output to screen.
See also: edit_history, run_history.
cmd_number ¶first last ¶Edit the history list using the editor named by the variable EDITOR.
The commands to be edited are first copied to a temporary file. When you
exit the editor, Octave executes the commands that remain in the file. It
is often more convenient to use edit_history to define functions
rather than attempting to enter them directly on the command line.
The block of commands is executed as soon as you exit the editor.
To avoid executing any commands, simply delete all the lines from the buffer
before leaving the editor.
When invoked with no arguments, edit the previously executed command; With one argument, edit the specified command cmd_number; With two arguments, edit the list of commands between first and last. Command number specifiers may also be negative where -1 refers to the most recently executed command. The following are equivalent and edit the most recently executed command.
edit_history edit_history -1
When using ranges, specifying a larger number for the first command than the last command reverses the list of commands before they are placed in the buffer to be edited.
See also: run_history, history.
cmd_number ¶first last ¶Run commands from the history list.
When invoked with no arguments, run the previously executed command;
With one argument, run the specified command cmd_number;
With two arguments, run the list of commands between first and last. Command number specifiers may also be negative where -1 refers to the most recently executed command. For example, the command
run_history
OR
run_history -1
executes the most recent command again. The command
run_history 13 169
executes commands 13 through 169.
Specifying a larger number for the first command than the last command reverses the list of commands before executing them. For example:
disp (1) disp (2) run_history -1 -2 ⇒ 2 1
See also: edit_history, history.
Octave also allows you customize the details of when, where, and how history is saved.
val = history_save () ¶old_val = history_save (new_val) ¶old_val = history_save (new_val, "local") ¶Query or set the internal variable that controls whether commands entered on the command line are saved in the history file.
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: history_control, history_file, history_size, history_timestamp_format_string.
val = history_control () ¶old_val = history_control (new_val) ¶Query or set the internal variable that specifies how commands are saved to the history list.
The default value is an empty character string, but may be overridden by the
environment variable OCTAVE_HISTCONTROL.
The value of history_control is a colon-separated list of values
controlling how commands are saved on the history list. If the list
of values includes ignorespace, lines which begin with a space
character are not saved in the history list. A value of ignoredups
causes lines matching the previous history entry to not be saved.
A value of ignoreboth is shorthand for ignorespace and
ignoredups. A value of erasedups causes all previous lines
matching the current line to be removed from the history list before that
line is saved. Any value not in the above list is ignored. If
history_control is the empty string, all commands are saved on
the history list, subject to the value of history_save.
See also: history_file, history_size, history_timestamp_format_string, history_save.
val = history_file () ¶old_val = history_file (new_val) ¶Query or set the internal variable that specifies the name of the file used to store command history.
All future commands issued during the current Octave session will be written to
this new file (if the current setting of history_save allows for this).
The default value is $DATA/octave/history, where
$DATA is the platform-specific location for (roaming) user data files
(e.g., $XDG_DATA_HOME or, if that is not set, ~/.local/share
on Unix-like operating systems or %APPDATA% on Windows). The default
value may be overridden by the environment variable OCTAVE_HISTFILE.
Programming Notes:
If you want to permanently change the location of Octave’s history file you
need to issue the history_file command in every new Octave session.
This can be achieved by using Octave’s .octaverc startup file.
If you also want to read the saved history commands of past Octave sessions
from this different history file, then you need to use the additional command
history -r after setting the new value of the history file. Example
code in Octave’s startup file to do this might look like this:
history_file ("~/new/.octave_hist");
if (exist (history_file ()))
history ("-r", history_file());
endif
See also: history, history_control, history_save, history_size, history_timestamp_format_string.
val = history_size () ¶old_val = history_size (new_val) ¶Query or set the internal variable that specifies how many entries to store in the history file.
The default value is 1000, but may be overridden by the environment
variable OCTAVE_HISTSIZE.
See also: history_file, history_timestamp_format_string, history_save.
val = history_timestamp_format_string () ¶old_val = history_timestamp_format_string (new_val) ¶old_val = history_timestamp_format_string (new_val, "local") ¶Query or set the internal variable that specifies the format string for the comment line that is written to the history file when Octave exits.
The format string is passed to strftime. The default value is
"# Octave VERSION, %a %b %d %H:%M:%S %Y %Z <USER@HOST>"
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: strftime, history_file, history_size, history_save.
val = EDITOR () ¶old_val = EDITOR (new_val) ¶old_val = EDITOR (new_val, "local") ¶Query or set the internal variable that specifies the default text editor.
The default value is taken from the environment variable EDITOR
when Octave starts. If the environment variable is not initialized,
EDITOR will be set to "emacs".
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: edit, edit_history.