octave-nkf: doc/interpreter/basics.txi comparison

comparison doc/interpreter/basics.txi @ 19628:fe689210525c gui-release

maint: Periodic merge of stable to gui-release.

author	John W. Eaton <jwe@octave.org>
date	Tue, 20 Jan 2015 10:05:42 -0500
parents	5971c8f515a7 446c46af4b42
children	0e1f5a750d00

comparison

equal deleted inserted replaced

-:6d75f1683ce8
+:fe689210525c
 @c
 @c Octave is free software; you can redistribute it and/or modify it
 @c under the terms of the GNU General Public License as published by the
 @c Free Software Foundation; either version 3 of the License, or (at
 @c your option) any later version.
 @c
 @c Octave is distributed in the hope that it will be useful, but WITHOUT
 @c ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 @c FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 @c for more details.
 @c
 @c You should have received a copy of the GNU General Public License
 @c along with Octave; see the file COPYING.  If not, see
 @c <http://www.gnu.org/licenses/>.
 @node Getting Started
 @cindex @code{-?}
 Print short help message and exit.
 @item --image-path @var{path}
 @cindex @code{--image-path @var{path}}
 Add path to the head of the search path for images.  The value of
 @var{path} specified on the command line will override any value of
 @w{@env{OCTAVE_IMAGE_PATH}} found in the environment, but not any commands
 in the system or user startup files that set the built-in variable
 @w{@env{IMAGE_PATH}}.
 @item --info-file @var{filename}
 @cindex @code{--info-file @var{filename}}
 Specify the name of the info file to use.  The value of @var{filename}
 @cindex @code{--no-init-file}
 Don't read the initialization files @file{~/.octaverc} and @file{.octaverc}.
 @item --no-init-path
 @cindex @code{--no-init-path}
 Don't initialize the search path for function files to include default
 locations.
 @item --no-line-editing
 @cindex @code{--no-line-editing}
 Disable command-line editing.
 @item  --path @var{path}
 @itemx -p @var{path}
 @cindex @code{--path @var{path}}
 @cindex @code{-p @var{path}}
 Add path to the head of the search path for function files.  The
 value of @var{path} specified on the command line will override any value
 of @w{@env{OCTAVE_PATH}} found in the environment, but not any commands in the
 system or user startup files that set the internal load path through one
 of the path functions.
 @item @var{file}
 Execute commands from @var{file}.  Exit when done unless
 @option{--persist} is also specified.
 @end table
 Octave also includes several functions which return information
 about the command line, including the number of arguments and all of the
 options.
 @DOCSTRING(argv)
 @DOCSTRING(program_name)
 @DOCSTRING(program_invocation_name)
 Here is an example of using these functions to reproduce the command
 line which invoked Octave.
 @example
 @group
 printf ("%s", program_name ());
 @end group
 @end example
 @noindent
 @xref{Indexing Cell Arrays}, for an explanation of how to retrieve objects
 from cell arrays, and @ref{Defining Functions}, for information about the
 variable @code{nargin}.
 @node Startup Files
 @subsection Startup Files
 @cindex initialization
 @table @code
 @item @var{octave-home}/share/octave/site/m/startup/octaverc
 @cindex site startup file
 where @var{octave-home} is the directory in which Octave is installed
 (the default is @file{/usr/local}).
 This file is provided so that changes to the default Octave environment
 can be made globally for all users at your site for all versions of Octave
 you have installed.  Care should be taken when making changes to this file
 since all users of Octave at your site will be affected.  The default file
 may be overridden by the environment variable @w{@env{OCTAVE_SITE_INITFILE}}.
 @item @var{octave-home}/share/octave/@var{version}/m/startup/octaverc
 @cindex version startup file
 where @var{octave-home} is the directory in which Octave is
 @w{@env{OCTAVE_VERSION_INITFILE}}.
 @item ~/.octaverc
 @cindex personal startup file
 @cindex @code{~/.octaverc}
 This file is used to make personal changes to the default
 Octave environment.
 @item .octaverc
 @cindex project startup file
 @cindex @code{.octaverc}
 @cindex editing the command line
 Octave uses the GNU Readline library to provide an extensive set of
 command-line editing and history features.  Only the most common
 features are described in this manual.  In addition, all of the editing
 functions can be bound to different key strokes at the user's discretion.
 This manual assumes no changes from the default Emacs bindings.  See the GNU
 Readline Library manual for more information on customizing Readline and
 for a complete feature list.
 To insert printing characters (letters, digits, symbols, etc.), simply
 type the character.  Octave will insert the character at the cursor and
 advance the cursor forward.
 characters.  For example, the character @kbd{Control-a} moves the cursor
 to the beginning of the line.  To type @kbd{C-a}, hold down @key{CTRL}
 and then press @key{a}.  In the following sections, control characters
 such as @kbd{Control-a} are written as @kbd{C-a}.
 Another set of command-line editing functions use Meta characters.  To
 type @kbd{M-u}, hold down the @key{META} key and press @key{u}.  Depending
 on the keyboard, the @key{META} key may be labeled @key{ALT} or
 even @key{WINDOWS}.  If your terminal does not have a @key{META} key, you
 can still type Meta characters using two-character sequences starting
 with @kbd{ESC}.  Thus, to enter @kbd{M-u}, you would type
 Kill from the cursor to the end of the current word, or if between
 words, to the end of the next word.
 @item M-@key{DEL}
 Kill from the cursor to the start of the previous word, or if between
 words, to the start of the previous word.
 @item C-w
 Kill from the cursor to the previous whitespace.  This is different than
 @kbd{M-@key{DEL}} because the word boundaries differ.
 @end table
 @item C-s
 Search forward starting at the current line and moving `down' through
 the history as necessary.
 @end table
 On most terminals, you can also use the up and down arrow keys in place
 of @kbd{C-p} and @kbd{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.
 In the example above, the first line indicates that a variable named
 @samp{x} was found to be undefined near line 1 and column 24 of some
 function or expression.  For errors occurring within functions, lines
 are counted from the beginning of the file containing the function
 definition.  For errors occurring outside of an enclosing function,
 the line number indicates the input line number, which is usually displayed
 in the primary prompt string.
 The second and third lines of the error message indicate that the error
 occurred within the function @code{f}.  If the function @code{f} had been
 called from within another function, for example, @code{g}, the list of
 errors would have ended with one more line:
 @example
 error:   g at line 1, column 17
 @end example
 printing the normal startup message, and to keep them from behaving
 differently depending on the contents of a particular user's
 @file{~/.octaverc} file.  @xref{Invoking Octave from the Command Line}.
 Note that some operating systems may place a limit on the number of
 characters that are recognized after @samp{#!}.  Also, the arguments
 appearing in a @samp{#!} line are parsed differently by various
 shells/systems.  The majority of them group all the arguments together in one
 string and pass it to the interpreter as a single argument.  In this case, the
 following script:
 @example
 @group
 @end group
 @end example
 @noindent
 which will produce an error message.  Unfortunately, it is
 not possible for Octave to determine whether it has been called from the
 command line or from a @samp{#!} script, so some care is needed when using the
 @samp{#!} mechanism.
 Note that when Octave is started from an executable script, the built-in
 function @code{argv} returns a cell array containing the command line
 @cindex comments
 @cindex use of comments
 @cindex documenting Octave programs
 A @dfn{comment} is some text that is included in a program for the sake
 of human readers, and which is NOT an executable part of the program.
 Comments can explain what the program does, and how it works.  Nearly all
 programming languages have provisions for comments, because programs are
 typically hard to understand without them.
 @menu
 shows whole line and partial line comments.
 @example
 @group
 function countdown
 # Count down for main rocket engines
 disp (3);
 disp (2);
 disp (1);
 disp ("Blast Off!");  # Rocket leaves pad
 endfunction
 @cindex block comments
 @cindex multi-line comments
 @cindex @samp{#@{}
 @cindex @samp{%@{}
 Entire blocks of code can be commented by enclosing the code between
 matching @samp{#@{} and @samp{#@}} or @samp{%@{} and @samp{%@}} markers.
 For example,
 @example
 @group
 function quick_countdown
 # Count down for main rocket engines
 disp (3);
 #@{
 disp (2);
 disp (1);
 #@}
 throw-away Octave programs, it usually isn't very useful because the
 purpose of a comment is to help you or another person understand the
 program at a later time.
 The @code{help} parser currently only recognizes single line comments
 (@pxref{Single Line Comments}) and not block comments for the initial
 help text.

Mercurial > octave-nkf

comparison doc/interpreter/basics.txi @ 19628:fe689210525c gui-release