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GNU Info File | 1996-10-12 | 47.9 KB | 1,275 lines

This is Info file octave.info, produced by Makeinfo-1.64 from the input file octave.texi. Copyright (C) 1993, 1994, 1995 John W. Eaton. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions. File: octave.info, Node: Bug Criteria, Next: Bug Lists, Prev: Reporting Bugs, Up: Trouble Have You Found a Bug? ===================== If you are not sure whether you have found a bug, here are some guidelines: * If Octave gets a fatal signal, for any input whatever, that is a bug. Reliable interpreters never crash. * If Octave produces incorrect results, for any input whatever, that is a bug. * Some output may appear to be incorrect when it is in fact due to a program whose behavior is undefined, which happened by chance to give the desired results on another system. For example, the range operator may produce different results because of differences in the way floating point arithmetic is handled on various systems. * If Octave produces an error message for valid input, that is a bug. * If Octave does not produce an error message for invalid input, that is a bug. However, you should note that your idea of "invalid input" might be my idea of "an extension" or "support for traditional practice". * If you are an experienced user of programs like Octave, your suggestions for improvement are welcome in any case. File: octave.info, Node: Bug Lists, Next: Bug Reporting, Prev: Bug Criteria, Up: Trouble Where to Report Bugs ==================== If you have Octave working at all, the easiest way to prepare a complete bug report is to use the Octave function `bug_report'. When you execute this function, Octave will prompt you for a subject and then invoke the editor on a file that already contains all the configuration information. When you exit the editor, Octave will mail the bug report for you. If for some reason you cannot use Octave's `bug_report' function, send bug reports for Octave to: bug-octave@che.utexas.edu *Do not send bug reports to `help-octave'*. Most users of Octave do not want to receive bug reports. Those that do have asked to be on `bug-octave'. As a last resort, send bug reports on paper to: Octave Bugs c/o John W. Eaton Department of Chemical Engineering The University of Texas at Austin Austin, Texas 78712 File: octave.info, Node: Bug Reporting, Next: Sending Patches, Prev: Bug Lists, Up: Trouble How to Report Bugs ================== The fundamental principle of reporting bugs usefully is this: *report all the facts*. If you are not sure whether to state a fact or leave it out, state it! Often people omit facts because they think they know what causes the problem and they conclude that some details don't matter. Thus, you might assume that the name of the variable you use in an example does not matter. Well, probably it doesn't, but one cannot be sure. Perhaps the bug is a stray memory reference which happens to fetch from the location where that name is stored in memory; perhaps, if the name were different, the contents of that location would fool the interpreter into doing the right thing despite the bug. Play it safe and give a specific, complete example. Keep in mind that the purpose of a bug report is to enable someone to fix the bug if it is not known. Always write your bug reports on the assumption that the bug is not known. Sometimes people give a few sketchy facts and ask, "Does this ring a bell?" This cannot help us fix a bug. It is better to send a complete bug report to begin with. Try to make your bug report self-contained. If we have to ask you for more information, it is best if you include all the previous information in your response, as well as the information that was missing. To enable someone to investigate the bug, you should include all these things: * The version of Octave. You can get this by noting the version number that is printed when Octave starts, or running it with the `-v' option. * A complete input file that will reproduce the bug. A single statement may not be enough of an example--the bug might depend on other details that are missing from the single statement where the error finally occurs. * The command arguments you gave Octave to execute that example and observe the bug. To guarantee you won't omit something important, list all the options. If we were to try to guess the arguments, we would probably guess wrong and then we would not encounter the bug. * The type of machine you are using, and the operating system name and version number. * The command-line arguments you gave to the `configure' command when you installed the interpreter. * A complete list of any modifications you have made to the interpreter source. Be precise about these changes--show a context diff for them. * Details of any other deviations from the standard procedure for installing Octave. * A description of what behavior you observe that you believe is incorrect. For example, "The interpreter gets a fatal signal," or, "The output produced at line 208 is incorrect." Of course, if the bug is that the interpreter gets a fatal signal, then one can't miss it. But if the bug is incorrect output, we might not notice unless it is glaringly wrong. Even if the problem you experience is a fatal signal, you should still say so explicitly. Suppose something strange is going on, such as, your copy of the interpreter is out of synch, or you have encountered a bug in the C library on your system. Your copy might crash and the copy here would not. If you said to expect a crash, then when the interpreter here fails to crash, we would know that the bug was not happening. If you don't say to expect a crash, then we would not know whether the bug was happening. We would not be able to draw any conclusion from our observations. Often the observed symptom is incorrect output when your program is run. Unfortunately, this is not enough information unless the program is short and simple. It is very helpful if you can include an explanation of the expected output, and why the actual output is incorrect. * If you wish to suggest changes to the Octave source, send them as context diffs. If you even discuss something in the Octave source, refer to it by context, not by line number, because the line numbers in the development sources probalby won't match those in your sources. Here are some things that are not necessary: * A description of the envelope of the bug. Often people who encounter a bug spend a lot of time investigating which changes to the input file will make the bug go away and which changes will not affect it. Such information is usually not necessary to enable us to fix bugs in Octave, but if you can find a simpler example to report *instead* of the original one, that is a convenience. Errors in the output will be easier to spot, running under the debugger will take less time, etc. Most Octave bugs involve just one function, so the most straightforward way to simplify an example is to delete all the function definitions except the one in which the bug occurs. However, simplification is not vital; if you don't want to do this, report the bug anyway and send the entire test case you used. * A patch for the bug. Patches can be helpful, but if you find a bug, you should report it, even if you cannot send a fix for the problem. File: octave.info, Node: Sending Patches, Next: Service, Prev: Bug Reporting, Up: Trouble Sending Patches for Octave ========================== If you would like to write bug fixes or improvements for Octave, that is very helpful. When you send your changes, please follow these guidelines to avoid causing extra work for us in studying the patches. If you don't follow these guidelines, your information might still be useful, but using it will take extra work. Maintaining Octave is a lot of work in the best of circumstances, and we can't keep up unless you do your best to help. * Send an explanation with your changes of what problem they fix or what improvement they bring about. For a bug fix, just include a copy of the bug report, and explain why the change fixes the bug. * Always include a proper bug report for the problem you think you have fixed. We need to convince ourselves that the change is right before installing it. Even if it is right, we might have trouble judging it if we don't have a way to reproduce the problem. * Include all the comments that are appropriate to help people reading the source in the future understand why this change was needed. * Don't mix together changes made for different reasons. Send them *individually*. If you make two changes for separate reasons, then we might not want to install them both. We might want to install just one. * Use `diff -c' to make your diffs. Diffs without context are hard for us to install reliably. More than that, they make it hard for us to study the diffs to decide whether we want to install them. Unidiff format is better than contextless diffs, but not as easy to read as `-c' format. If you have GNU diff, use `diff -cp', which shows the name of the function that each change occurs in. * Write the change log entries for your changes. Read the `ChangeLog' file to see what sorts of information to put in, and to learn the style that we use. The purpose of the change log is to show people where to find what was changed. So you need to be specific about what functions you changed; in large functions, it's often helpful to indicate where within the function the change was made. On the other hand, once you have shown people where to find the change, you need not explain its purpose. Thus, if you add a new function, all you need to say about it is that it is new. If you feel that the purpose needs explaining, it probably does--but the explanation will be much more useful if you put it in comments in the code. If you would like your name to appear in the header line for who made the change, send us the header line. File: octave.info, Node: Service, Prev: Sending Patches, Up: Trouble How To Get Help with Octave =========================== If you need help installing, using or changing Octave, the mailing list help-octave@che.utexas.edu exists for the discussion of Octave matters related to using, installing, and porting Octave. If you would like to join the discussion, please send a short note to help-octave-request@che.utexas.edu ^^^^^^^ *Please do not* send requests to be added or removed from the the mailing list, or other administrative trivia to the list itself. File: octave.info, Node: Command Line Editing, Next: Using Info, Prev: Trouble, Up: Top Command Line Editing ******************** This text describes GNU's command line editing interface. It is relatively old and may not be entirely correct now. Please send a message to `bug-octave@che.utexas.edu' if you find any errors. *Note Reporting Bugs::, for more information about how to report bugs. * Menu: * Introduction and Notation:: Notation used in this text. * Readline Interaction:: The minimum set of commands for editing a line. * Readline Bare Essentials:: * Readline Movement Commands:: * Readline Killing Commands:: * Readline Arguments:: * Readline Init File:: Customizing Readline from a user's view. * Readline Init Syntax:: * Readline Vi Mode:: File: octave.info, Node: Introduction and Notation, Next: Readline Interaction, Prev: Command Line Editing, Up: Command Line Editing Introduction to Line Editing ============================ The following paragraphs describe the notation we use to represent keystrokes. The text C-k is read as `Control-K' and describes the character produced when the Control key is depressed and the k key is struck. The text M-k is read as `Meta-K' and describes the character produced when the meta key (if you have one) is depressed, and the k key is struck. If you do not have a meta key, the identical keystroke can be generated by typing ESC first, and then typing k. Either process is known as "metafying" the k key. The text M-C-k is read as `Meta-Control-k' and describes the character produced by "metafying" C-k. In addition, several keys have their own names. Specifically, DEL, ESC, LFD, SPC, RET, and TAB all stand for themselves when seen in this text, or in an init file (*note Readline Init File::., for more info). File: octave.info, Node: Readline Interaction, Next: Readline Bare Essentials, Prev: Introduction and Notation, Up: Command Line Editing Readline Interaction ==================== Often during an interactive session you type in a long line of text, only to notice that the first word on the line is misspelled. The Readline library gives you a set of commands for manipulating the text as you type it in, allowing you to just fix your typo, and not forcing you to retype the majority of the line. Using these editing commands, you move the cursor to the place that needs correction, and delete or insert the text of the corrections. Then, when you are satisfied with the line, you simply press RETURN. You do not have to be at the end of the line to press RETURN; the entire line is accepted regardless of the location of the cursor within the line. * Menu: * Readline Bare Essentials:: The least you need to know about Readline. * Readline Movement Commands:: Moving about the input line. * Readline Killing Commands:: How to delete text, and how to get it back! * Readline Arguments:: Giving numeric arguments to commands. File: octave.info, Node: Readline Bare Essentials, Next: Readline Movement Commands, Prev: Readline Interaction, Up: Command Line Editing Readline Bare Essentials ======================== In order to enter characters into the line, simply type them. The typed character appears where the cursor was, and then the cursor moves one space to the right. If you mistype a character, you can use DEL to back up, and delete the mistyped character. Sometimes you may miss typing a character that you wanted to type, and not notice your error until you have typed several other characters. In that case, you can type C-b to move the cursor to the left, and then correct your mistake. Afterwards, you can move the cursor to the right with C-f. When you add text in the middle of a line, you will notice that characters to the right of the cursor get `pushed over' to make room for the text that you have inserted. Likewise, when you delete text behind the cursor, characters to the right of the cursor get `pulled back' to fill in the blank space created by the removal of the text. A list of the basic bare essentials for editing the text of an input line follows. C-b Move back one character. C-f Move forward one character. DEL Delete the character to the left of the cursor. C-d Delete the character underneath the cursor. Printing characters Insert itself into the line at the cursor. C-_ Undo the last thing that you did. You can undo all the way back to an empty line. File: octave.info, Node: Readline Movement Commands, Next: Readline Killing Commands, Prev: Readline Bare Essentials, Up: Command Line Editing Readline Movement Commands ========================== The above table describes the most basic possible keystrokes that you need in order to do editing of the input line. For your convenience, many other commands have been added in addition to C-b, C-f, C-d, and DEL. Here are some commands for moving more rapidly about the line. C-a Move to the start of the line. C-e Move to the end of the line. M-f Move forward a word. M-b Move backward a word. C-l Clear the screen, reprinting the current line at the top. Notice how C-f moves forward a character, while M-f moves forward a word. It is a loose convention that control keystrokes operate on characters while meta keystrokes operate on words. File: octave.info, Node: Readline Killing Commands, Next: Readline Arguments, Prev: Readline Movement Commands, Up: Command Line Editing Readline Killing Commands ========================= "Killing" text means to delete the text from the line, but to save it away for later use, usually by "yanking" it back into the line. If the description for a command says that it `kills' text, then you can be sure that you can get the text back in a different (or the same) place later. Here is the list of commands for killing text. C-k Kill the text from the current cursor position to the end of the line. M-d Kill from the cursor to the end of the current word, or if between words, to the end of the next word. M-DEL Kill from the cursor to the start of the previous word, or if between words, to the start of the previous word. C-w Kill from the cursor to the previous whitespace. This is different than M-DEL because the word boundaries differ. And, here is how to "yank" the text back into the line. Yanking is C-y Yank the most recently killed text back into the buffer at the cursor. M-y Rotate the kill-ring, and yank the new top. You can only do this if the prior command is C-y or M-y. When you use a kill command, the text is saved in a "kill-ring". Any number of consecutive kills save all of the killed text together, so that when you yank it back, you get it in one clean sweep. The kill ring is not line specific; the text that you killed on a previously typed line is available to be yanked back later, when you are typing another line. File: octave.info, Node: Readline Arguments, Next: Readline Init File, Prev: Readline Killing Commands, Up: Command Line Editing Readline Arguments ================== You can pass numeric arguments to Readline commands. Sometimes the argument acts as a repeat count, other times it is the sign of the argument that is significant. If you pass a negative argument to a command which normally acts in a forward direction, that command will act in a backward direction. For example, to kill text back to the start of the line, you might type M- C-k. The general way to pass numeric arguments to a command is to type meta digits before the command. If the first `digit' you type is a minus sign (-), then the sign of the argument will be negative. Once you have typed one meta digit to get the argument started, you can type the remainder of the digits, and then the command. For example, to give the C-d command an argument of 10, you could type M-1 0 C-d. File: octave.info, Node: Readline Init File, Next: Readline Init Syntax, Prev: Readline Arguments, Up: Command Line Editing Readline Init File ================== Although the Readline library comes with a set of Emacs-like keybindings, it is possible that you would like to use a different set of keybindings. You can customize programs that use Readline by putting commands in an "init" file in your home directory. The name of this file is `~/.inputrc'. When a program which uses the Readline library starts up, the `~/.inputrc' file is read, and the keybindings are set. In addition, the C-x C-r command re-reads this init file, thus incorporating any changes that you might have made to it. * Menu: * Readline Init Syntax:: Syntax for the commands in `~/.inputrc'. * Readline Vi Mode:: Switching to `vi' mode in Readline. File: octave.info, Node: Readline Init Syntax, Next: Readline Vi Mode, Prev: Readline Init File, Up: Command Line Editing Readline Init Syntax ==================== There are only four constructs allowed in the `~/.inputrc' file: Variable Settings You can change the state of a few variables in Readline. You do this by using the `set' command within the init file. Here is how you would specify that you wish to use Vi line editing commands: set editing-mode vi Right now, there are only a few variables which can be set; so few in fact, that we just iterate them here: `editing-mode' The `editing-mode' variable controls which editing mode you are using. By default, GNU Readline starts up in Emacs editing mode, where the keystrokes are most similar to Emacs. This variable can either be set to `emacs' or `vi'. `horizontal-scroll-mode' This variable can either be set to `On' or `Off'. Setting it to `On' means that the text of the lines that you edit will scroll horizontally on a single screen line when they are larger than the width of the screen, instead of wrapping onto a new screen line. By default, this variable is set to `Off'. `mark-modified-lines' This variable when set to `On', says to display an asterisk (`*') at the starts of history lines which have been modified. This variable is off by default. `prefer-visible-bell' If this variable is set to `On' it means to use a visible bell if one is available, rather than simply ringing the terminal bell. By default, the value is `Off'. Key Bindings The syntax for controlling keybindings in the `~/.inputrc' file is simple. First you have to know the name of the command that you want to change. The following pages contain tables of the command name, the default keybinding, and a short description of what the command does. Once you know the name of the command, simply place the name of the key you wish to bind the command to, a colon, and then the name of the command on a line in the `~/.inputrc' file. The name of the key can be expressed in different ways, depending on which is most comfortable for you. KEYNAME: FUNCTION-NAME or MACRO KEYNAME is the name of a key spelled out in English. For example: Control-u: universal-argument Meta-Rubout: backward-kill-word Control-o: ">&output" In the above example, C-u is bound to the function `universal-argument', and C-o is bound to run the macro expressed on the right hand side (that is, to insert the text `>&output' into the line). "KEYSEQ": FUNCTION-NAME or MACRO KEYSEQ differs from KEYNAME above in that strings denoting an entire key sequence can be specified. Simply place the key sequence in double quotes. GNU Emacs style key escapes can be used, as in the following example: "\C-u": universal-argument "\C-x\C-r": re-read-init-file "\e[11~": "Function Key 1" In the above example, C-u is bound to the function `universal-argument' (just as it was in the first example), C-x C-r is bound to the function `re-read-init-file', and ESC [ 1 1 ~ is bound to insert the text `Function Key 1'. * Menu: * Commands For Moving:: Moving about the line. * Commands For History:: Getting at previous lines. * Commands For Text:: Commands for changing text. * Commands For Killing:: Commands for killing and yanking. * Numeric Arguments:: Specifying numeric arguments, repeat counts. * Commands For Completion:: Getting Readline to do the typing for you. * Miscellaneous Commands:: Other miscellaneous commands. File: octave.info, Node: Commands For Moving, Next: Commands For History, Prev: Readline Init Syntax, Up: Readline Init Syntax Commands For Moving ------------------- `beginning-of-line (C-a)' Move to the start of the current line. `end-of-line (C-e)' Move to the end of the line. `forward-char (C-f)' Move forward a character. `backward-char (C-b)' Move back a character. `forward-word (M-f)' Move forward to the end of the next word. `backward-word (M-b)' Move back to the start of this, or the previous, word. `clear-screen (C-l)' Clear the screen leaving the current line at the top of the screen. File: octave.info, Node: Commands For History, Next: Commands For Text, Prev: Commands For Moving, Up: Readline Init Syntax Commands For Manipulating The History ------------------------------------- `accept-line (Newline, Return)' Accept the line regardless of where the cursor is. If this line is non-empty, add it to the history list. If this line was a history line, then restore the history line to its original state. `previous-history (C-p)' Move `up' through the history list. `next-history (C-n)' Move `down' through the history list. `beginning-of-history (M-<)' Move to the first line in the history. `end-of-history (M->)' Move to the end of the input history, i.e., the line you are entering! `reverse-search-history (C-r)' Search backward starting at the current line and moving `up' through the history as necessary. This is an incremental search. `forward-search-history (C-s)' Search forward starting at the current line and moving `down' through the the history as necessary. File: octave.info, Node: Commands For Text, Next: Commands For Killing, Prev: Commands For History, Up: Readline Init Syntax Commands For Changing Text -------------------------- `delete-char (C-d)' Delete the character under the cursor. If the cursor is at the beginning of the line, and there are no characters in the line, and the last character typed was not C-d, then return EOF. `backward-delete-char (Rubout)' Delete the character behind the cursor. A numeric arg says to kill the characters instead of deleting them. `quoted-insert (C-q, C-v)' Add the next character that you type to the line verbatim. This is how to insert things like C-q for example. `tab-insert (M-TAB)' Insert a tab character. `self-insert (a, b, A, 1, !, ...)' Insert yourself. `transpose-chars (C-t)' Drag the character before point forward over the character at point. Point moves forward as well. If point is at the end of the line, then transpose the two characters before point. Negative args don't work. `transpose-words (M-t)' Drag the word behind the cursor past the word in front of the cursor moving the cursor over that word as well. `upcase-word (M-u)' Uppercase the current (or following) word. With a negative argument, do the previous word, but do not move point. `downcase-word (M-l)' Lowercase the current (or following) word. With a negative argument, do the previous word, but do not move point. `capitalize-word (M-c)' Uppercase the current (or following) word. With a negative argument, do the previous word, but do not move point. File: octave.info, Node: Commands For Killing, Next: Numeric Arguments, Prev: Commands For Text, Up: Readline Init Syntax Killing And Yanking ------------------- `kill-line (C-k)' Kill the text from the current cursor position to the end of the line. `backward-kill-line ()' Kill backward to the beginning of the line. This is normally unbound. `kill-word (M-d)' Kill from the cursor to the end of the current word, or if between words, to the end of the next word. `backward-kill-word (M-DEL)' Kill the word behind the cursor. `unix-line-discard (C-u)' Do what C-u used to do in Unix line input. We save the killed text on the kill-ring, though. `unix-word-rubout (C-w)' Do what C-w used to do in Unix line input. The killed text is saved on the kill-ring. This is different than backward-kill-word because the word boundaries differ. `yank (C-y)' Yank the top of the kill ring into the buffer at point. `yank-pop (M-y)' Rotate the kill-ring, and yank the new top. You can only do this if the prior command is yank or yank-pop. File: octave.info, Node: Numeric Arguments, Next: Commands For Completion, Prev: Commands For Killing, Up: Readline Init Syntax Specifying Numeric Arguments ---------------------------- `digit-argument (M-0, M-1, ... M--)' Add this digit to the argument already accumulating, or start a new argument. M- starts a negative argument. `universal-argument ()' Do what C-u does in emacs. By default, this is not bound. File: octave.info, Node: Commands For Completion, Next: Miscellaneous Commands, Prev: Numeric Arguments, Up: Readline Init Syntax Letting Readline Type For You ----------------------------- `complete (TAB)' Attempt to do completion on the text before point. This is implementation defined. Generally, if you are typing a file name argument, you can do file name completion; if you are typing a command, you can do command completion, if you are typing in a symbol to GDB, you can do symbol name completion, if you are typing in a variable to Bash, you can do variable name completion... `possible-completions (M-?)' List the possible completions of the text before point. File: octave.info, Node: Miscellaneous Commands, Prev: Commands For Completion, Up: Readline Init Syntax Some Miscellaneous Commands --------------------------- `re-read-init-file (C-x C-r)' Read in the contents of your `~/.inputrc' file, and incorporate any bindings found there. `abort (C-g)' Ding! Stops things. `do-uppercase-version (M-a, M-b, ...)' Run the command that is bound to your uppercase brother. `prefix-meta (ESC)' Make the next character that you type be metafied. This is for people without a meta key. Typing ESC f is equivalent to typing M-f. `undo (C-_)' Incremental undo, separately remembered for each line. `revert-line (M-r)' Undo all changes made to this line. This is like typing the `undo' command enough times to get back to the beginning. File: octave.info, Node: Readline Vi Mode, Prev: Readline Init Syntax, Up: Command Line Editing Readline Vi Mode ================ While the Readline library does not have a full set of Vi editing functions, it does contain enough to allow simple editing of the line. In order to switch interactively between Emacs and Vi editing modes, use the command M-C-j (toggle-editing-mode). When you enter a line in Vi mode, you are already placed in `insertion' mode, as if you had typed an `i'. Pressing ESC switches you into `edit' mode, where you can edit the text of the line with the standard Vi movement keys, move to previous history lines with `k', and following lines with `j', and so forth. File: octave.info, Node: Using Info, Next: Concept Index, Prev: Command Line Editing, Up: Top Using Info ********** * Menu: * Cursor Commands:: * Scrolling Commands:: * Node Commands:: * Searching Commands:: * Xref Commands:: * Window Commands:: * Printing Nodes:: * Other Info Commands:: * Info Variables:: "Info" is a program which is used to view info files on an ASCII terminal. "info files" are the result of processing texinfo files with the program `makeinfo' or with the Emacs command `M-x texinfo-format-buffer'. Finally, "texinfo" is a documentation language which allows a printed manual and on-line documentation (an info file) to be produced from a single source file. * Menu: * Cursor Commands:: Commands which move the cursor within a node. * Scrolling Commands:: Commands for moving the node around in a window. * Node Commands:: Commands for selecting a new node. * Searching Commands:: Commands for searching an info file. * Xref Commands:: Commands for selecting cross references. * Window Commands:: Commands which manipulate multiple windows. * Printing Nodes:: How to print out the contents of a node. * Other Info Commands:: A few commands that defy categories. * Info Variables:: How to change the default behavior of Info. File: octave.info, Node: Cursor Commands, Next: Scrolling Commands, Prev: Using Info, Up: Using Info Moving the Cursor ================= Many people find that reading screens of text page by page is made easier when one is able to indicate particular pieces of text with some kind of pointing device. Since this is the case, GNU Info (both the Emacs and standalone versions) have several commands which allow you to move the cursor about the screen. The notation used in this manual to describe keystrokes is identical to the notation used within the Emacs manual, and the GNU Readline manual. *Note Character Conventions: (emacs)Characters, if you are unfamiliar with the notation. The following table lists the basic cursor movement commands in Info. Each entry consists of the key sequence you should type to execute the cursor movement, the `M-x'(1) command name (displayed in parentheses), and a short description of what the command does. All of the cursor motion commands can take an "numeric" argument (*note `universal-argument': Other Info Commands.), to find out how to supply them. With a numeric argument, the motion commands are simply executed that many times; for example, a numeric argument of 4 given to `next-line' causes the cursor to move down 4 lines. With a negative numeric argument, the motion is reversed; an argument of -4 given to the `next-line' command would cause the cursor to move *up* 4 lines. `C-n' (`next-line') Moves the cursor down to the next line. `C-p' (`prev-line') Move the cursor up to the previous line. `C-a' (`beginning-of-line') Move the cursor to the start of the current line. `C-e' (`end-of-line') Moves the cursor to the end of the current line. `C-f' (`forward-char') Move the cursor forward a character. `C-b' (`backward-char') Move the cursor backward a character. `M-f' (`forward-word') Moves the cursor forward a word. `M-b' (`backward-word') Moves the cursor backward a word. `M-<' (`beginning-of-node') `b' Moves the cursor to the start of the current node. `M->' (`end-of-node') Moves the cursor to the end of the current node. `M-r' (`move-to-window-line') Moves the cursor to a specific line of the window. Without a numeric argument, `M-r' moves the cursor to the start of the line in the center of the window. With a numeric argument of N, `M-r' moves the cursor to the start of the Nth line in the window. ---------- Footnotes ---------- (1) `M-x' is also a command; it invokes `execute-extended-command'. *Note Executing an extended command: (emacs)M-x, for more detailed information. File: octave.info, Node: Scrolling Commands, Next: Node Commands, Prev: Cursor Commands, Up: Using Info Moving Text Within a Window =========================== Sometimes you are looking at a screenful of text, and only part of the current paragraph you are reading is visible on the screen. The commands detailed in this section are used to shift which part of the current node is visible on the screen. `SPC' (`scroll-forward') `C-v' Shift the text in this window up. That is, show more of the node which is currently below the bottom of the window. With a numeric argument, show that many more lines at the bottom of the window; a numeric argument of 4 would shift all of the text in the window up 4 lines (discarding the top 4 lines), and show you four new lines at the bottom of the window. Without a numeric argument, SPC takes the bottom two lines of the window and places them at the top of the window, redisplaying almost a completely new screenful of lines. `DEL' (`scroll-backward') `M-v' Shift the text in this window down. The inverse of `scroll-forward'. The `scroll-forward' and `scroll-backward' commands can also move forward and backward through the node structure of the file. If you press SPC while viewing the end of a node, or DEL while viewing the beginning of a node, what happens is controlled by the variable `scroll-behaviour'. *Note `scroll-behaviour': Info Variables, for more information. `C-l' (`redraw-display') Redraw the display from scratch, or shift the line containing the cursor to a specified location. With no numeric argument, `C-l' clears the screen, and then redraws its entire contents. Given a numeric argument of N, the line containing the cursor is shifted so that it is on the Nth line of the window. `C-x w' (`toggle-wrap') Toggles the state of line wrapping in the current window. Normally, lines which are longer than the screen width "wrap", i.e., they are continued on the next line. Lines which wrap have a `\' appearing in the rightmost column of the screen. You can cause such lines to be terminated at the rightmost column by changing the state of line wrapping in the window with `C-x w'. When a line which needs more space than one screen width to display is displayed, a `$' appears in the rightmost column of the screen, and the remainder of the line is invisible. File: octave.info, Node: Node Commands, Next: Searching Commands, Prev: Scrolling Commands, Up: Using Info Selecting a New Node ==================== This section details the numerous Info commands which select a new node to view in the current window. The most basic node commands are `n', `p', `u', and `l'. When you are viewing a node, the top line of the node contains some Info "pointers" which describe where the next, previous, and up nodes are. Info uses this line to move about the node structure of the file when you use the following commands: `n' (`next-node') Selects the `Next' node. `p' (`prev-node') Selects the `Prev' node. `u' (`up-node') Selects the `Up' node. You can easily select a node that you have already viewed in this window by using the `l' command - this name stands for "last", and actually moves through the list of already visited nodes for this window. `l' with a negative numeric argument moves forward through the history of nodes for this window, so you can quickly step between two adjacent (in viewing history) nodes. `l' (`history-node') Selects the most recently selected node in this window. Two additional commands make it easy to select the most commonly selected nodes; they are `t' and `d'. `t' (`top-node') Selects the node `Top' in the current info file. `d' (`dir-node') Selects the directory node (i.e., the node `(dir)'). Here are some other commands which immediately result in the selection of a different node in the current window: `<' (`first-node') Selects the first node which appears in this file. This node is most often `Top', but it doesn't have to be. `>' (`last-node') Selects the last node which appears in this file. `]' (`global-next-node') Moves forward or down through node structure. If the node that you are currently viewing has a `Next' pointer, that node is selected. Otherwise, if this node has a menu, the first menu item is selected. If there is no `Next' and no menu, the same process is tried with the `Up' node of this node. `[' (`global-prev-node') Moves backward or up through node structure. If the node that you are currently viewing has a `Prev' pointer, that node is selected. Otherwise, if the node has an `Up' pointer, that node is selected, and if it has a menu, the last item in the menu is selected. You can get the same behavior as `global-next-node' and `global-prev-node' while simply scrolling through the file with SPC and DEL; *Note `scroll-behaviour': Info Variables, for more information. `g' (`goto-node') Reads the name of a node and selects it. No completion is done while reading the node name, since the desired node may reside in a separate file. The node must be typed exactly as it appears in the info file. A file name may be included as with any node specification, for example `g(emacs)Buffers' finds the node `Buffers' in the info file `emacs'. `C-x k' (`kill-node') Kills a node. The node name is prompted for in the echo area, with a default of the current node. "Killing" a node means that Info tries hard to forget about it, removing it from the list of history nodes kept for the window where that node is found. Another node is selected in the window which contained the killed node. `C-x C-f' (`view-file') Reads the name of a file and selects the entire file. The command `C-x C-f FILENAME' is equivalent to typing `g(FILENAME)*' `C-x C-b' (`list-visited-nodes') Makes a window containing a menu of all of the currently visited nodes. This window becomes the selected window, and you may use the standard Info commands within it. `C-x b' (`select-visited-node') Selects a node which has been previously visited in a visible window. This is similar to `C-x C-b' followed by `m', but no window is created. File: octave.info, Node: Searching Commands, Next: Xref Commands, Prev: Node Commands, Up: Using Info Searching an Info File ====================== GNU Info allows you to search for a sequence of characters throughout an entire info file, search through the indices of an info file, or find areas within an info file which discuss a particular topic. `s' (`search') Reads a string in the echo area and searches for it. `C-s' (`isearch-forward') Interactively searches forward through the info file for a string as you type it. `C-r' (`isearch-backward') Interactively searches backward through the info file for a string as you type it. `i' (`index-search') Looks up a string in the indices for this info file, and selects a node where the found index entry points to. `,' (`next-index-match') Moves to the node containing the next matching index item from the last `i' command. The most basic searching command is `s' (`search'). The `s' command prompts you for a string in the echo area, and then searches the remainder of the info file for an occurrence of that string. If the string is found, the node containing it is selected, and the cursor is left positioned at the start of the found string. Subsequent `s' commands show you the default search string within `[' and `]'; pressing RET instead of typing a new string will use the default search string. "Incremental searching" is similar to basic searching, but the string is looked up while you are typing it, instead of waiting until the entire search string has been specified. File: octave.info, Node: Xref Commands, Next: Window Commands, Prev: Searching Commands, Up: Using Info Selecting Cross References ========================== We have already discussed the `Next', `Prev', and `Up' pointers which appear at the top of a node. In addition to these pointers, a node may contain other pointers which refer you to a different node, perhaps in another info file. Such pointers are called "cross references", or "xrefs" for short. * Menu: * Parts of an Xref:: What a cross reference is made of. * Selecting Xrefs:: Commands for selecting menu or note items. File: octave.info, Node: Parts of an Xref, Next: Selecting Xrefs, Prev: Xref Commands, Up: Xref Commands Parts of an Xref ---------------- Cross references have two major parts: the first part is called the "label"; it is the name that you can use to refer to the cross reference, and the second is the "target"; it is the full name of the node that the cross reference points to. The target is separated from the label by a colon `:'; first the label appears, and then the target. For example, in the sample menu cross reference below, the single colon separates the label from the target. * Foo Label: Foo Target. More information about Foo. Note the `.' which ends the name of the target. The `.' is not part of the target; it serves only to let Info know where the target name ends. A shorthand way of specifying references allows two adjacent colons to stand for a target name which is the same as the label name: * Foo Commands:: Commands pertaining to Foo. In the above example, the name of the target is the same as the name of the label, in this case `Foo Commands'. You will normally see two types of cross references while viewing nodes: "menu" references, and "note" references. Menu references appear within a node's menu; they begin with a `*' at the beginning of a line, and continue with a label, a target, and a comment which describes what the contents of the node pointed to contains. Note references appear within the body of the node text; they begin with `*Note', and continue with a label and a target. Like `Next', `Prev' and `Up' pointers, cross references can point to any valid node. They are used to refer you to a place where more detailed information can be found on a particular subject. Here is a cross reference which points to a node within the Texinfo documentation: *Note Writing an Xref: (texinfo)xref, for more information on creating your own texinfo cross references. File: octave.info, Node: Selecting Xrefs, Prev: Parts of an Xref, Up: Xref Commands Selecting Xrefs --------------- The following table lists the Info commands which operate on menu items. `1' (`menu-digit') `2' ... `9' Within an Info window, pressing a single digit, (such as `1'), selects that menu item, and places its node in the current window. For convenience, there is one exception; pressing `0' selects the *last* item in the node's menu. `0' (`last-menu-item') Select the last item in the current node's menu. `m' (`menu-item') Reads the name of a menu item in the echo area and selects its node. Completion is available while reading the menu label. `M-x find-menu' Moves the cursor to the start of this node's menu. This table lists the Info commands which operate on note cross references. `f' (`xref-item') `r' Reads the name of a note cross reference in the echo area and selects its node. Completion is available while reading the cross reference label. Finally, the next few commands operate on menu or note references alike: `TAB' (`move-to-next-xref') Moves the cursor to the start of the next nearest menu item or note reference in this node. You can then use RET (`select-reference-this-line' to select the menu or note reference. `M-TAB' (`move-to-prev-xref') Moves the cursor the start of the nearest previous menu item or note reference in this node. `RET' (`select-reference-this-line') Selects the menu item or note reference appearing on this line. File: octave.info, Node: Window Commands, Next: Printing Nodes, Prev: Xref Commands, Up: Using Info Manipulating Multiple Windows ============================= A "window" is a place to show the text of a node. Windows have a view area where the text of the node is displayed, and an associated "mode line", which briefly describes the node being viewed. GNU Info supports multiple windows appearing in a single screen; each window is separated from the next by its modeline. At any time, there is only one "active" window, that is, the window in which the cursor appears. There are commands available for creating windows, changing the size of windows, selecting which window is active, and for deleting windows. * Menu: * The Mode Line:: What appears in the mode line? * Basic Windows:: Manipulating windows in Info. * The Echo Area:: Used for displaying errors and reading input.