This is Info file ./gdb.info, produced by Makeinfo version 1.68 from the input file gdb.texinfo. START-INFO-DIR-ENTRY * Gdb: (gdb). The GNU debugger. END-INFO-DIR-ENTRY This file documents the GNU debugger GDB. This is the Seventh Edition, February 1999, of `Debugging with GDB: the GNU Source-Level Debugger' for GDB Version 4.18. Copyright (C) 1988-1999 Free Software Foundation, Inc. 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 also 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: gdb.info, Node: Emacs, Next: GDB Bugs, Prev: Sequences, Up: Top Using GDB under GNU Emacs ************************* A special interface allows you to use GNU Emacs to view (and edit) the source files for the program you are debugging with GDB. To use this interface, use the command `M-x gdb' in Emacs. Give the executable file you want to debug as an argument. This command starts GDB as a subprocess of Emacs, with input and output through a newly created Emacs buffer. Using GDB under Emacs is just like using GDB normally except for two things: * All "terminal" input and output goes through the Emacs buffer. This applies both to GDB commands and their output, and to the input and output done by the program you are debugging. This is useful because it means that you can copy the text of previous commands and input them again; you can even use parts of the output in this way. All the facilities of Emacs' Shell mode are available for interacting with your program. In particular, you can send signals the usual way--for example, `C-c C-c' for an interrupt, `C-c C-z' for a stop. * GDB displays source code through Emacs. Each time GDB displays a stack frame, Emacs automatically finds the source file for that frame and puts an arrow (`=>') at the left margin of the current line. Emacs uses a separate buffer for source display, and splits the screen to show both your GDB session and the source. Explicit GDB `list' or search commands still produce output as usual, but you probably have no reason to use them from Emacs. *Warning:* If the directory where your program resides is not your current directory, it can be easy to confuse Emacs about the location of the source files, in which case the auxiliary display buffer does not appear to show your source. GDB can find programs by searching your environment's `PATH' variable, so the GDB input and output session proceeds normally; but Emacs does not get enough information back from GDB to locate the source files in this situation. To avoid this problem, either start GDB mode from the directory where your program resides, or specify an absolute file name when prompted for the `M-x gdb' argument. A similar confusion can result if you use the GDB `file' command to switch to debugging a program in some other location, from an existing GDB buffer in Emacs. By default, `M-x gdb' calls the program called `gdb'. If you need to call GDB by a different name (for example, if you keep several configurations around, with different names) you can set the Emacs variable `gdb-command-name'; for example, (setq gdb-command-name "mygdb") (preceded by `ESC ESC', or typed in the `*scratch*' buffer, or in your `.emacs' file) makes Emacs call the program named "`mygdb'" instead. In the GDB I/O buffer, you can use these special Emacs commands in addition to the standard Shell mode commands: `C-h m' Describe the features of Emacs' GDB Mode. `M-s' Execute to another source line, like the GDB `step' command; also update the display window to show the current file and location. `M-n' Execute to next source line in this function, skipping all function calls, like the GDB `next' command. Then update the display window to show the current file and location. `M-i' Execute one instruction, like the GDB `stepi' command; update display window accordingly. `M-x gdb-nexti' Execute to next instruction, using the GDB `nexti' command; update display window accordingly. `C-c C-f' Execute until exit from the selected stack frame, like the GDB `finish' command. `M-c' Continue execution of your program, like the GDB `continue' command. *Warning:* In Emacs v19, this command is `C-c C-p'. `M-u' Go up the number of frames indicated by the numeric argument (*note Numeric Arguments: (Emacs)Arguments.), like the GDB `up' command. *Warning:* In Emacs v19, this command is `C-c C-u'. `M-d' Go down the number of frames indicated by the numeric argument, like the GDB `down' command. *Warning:* In Emacs v19, this command is `C-c C-d'. `C-x &' Read the number where the cursor is positioned, and insert it at the end of the GDB I/O buffer. For example, if you wish to disassemble code around an address that was displayed earlier, type `disassemble'; then move the cursor to the address display, and pick up the argument for `disassemble' by typing `C-x &'. You can customize this further by defining elements of the list `gdb-print-command'; once it is defined, you can format or otherwise process numbers picked up by `C-x &' before they are inserted. A numeric argument to `C-x &' indicates that you wish special formatting, and also acts as an index to pick an element of the list. If the list element is a string, the number to be inserted is formatted using the Emacs function `format'; otherwise the number is passed as an argument to the corresponding list element. In any source file, the Emacs command `C-x SPC' (`gdb-break') tells GDB to set a breakpoint on the source line point is on. If you accidentally delete the source-display buffer, an easy way to get it back is to type the command `f' in the GDB buffer, to request a frame display; when you run under Emacs, this recreates the source buffer if necessary to show you the context of the current frame. The source files displayed in Emacs are in ordinary Emacs buffers which are visiting the source files in the usual way. You can edit the files with these buffers if you wish; but keep in mind that GDB communicates with Emacs in terms of line numbers. If you add or delete lines from the text, the line numbers that GDB knows cease to correspond properly with the code.  File: gdb.info, Node: GDB Bugs, Next: Formatting Documentation, Prev: Emacs, Up: Top Reporting Bugs in GDB ********************* Your bug reports play an essential role in making GDB reliable. Reporting a bug may help you by bringing a solution to your problem, or it may not. But in any case the principal function of a bug report is to help the entire community by making the next version of GDB work better. Bug reports are your contribution to the maintenance of GDB. In order for a bug report to serve its purpose, you must include the information that enables us to fix the bug. * Menu: * Bug Criteria:: Have you found a bug? * Bug Reporting:: How to report bugs  File: gdb.info, Node: Bug Criteria, Next: Bug Reporting, Prev: GDB Bugs, Up: GDB Bugs Have you found a bug? ===================== If you are not sure whether you have found a bug, here are some guidelines: * If the debugger gets a fatal signal, for any input whatever, that is a GDB bug. Reliable debuggers never crash. * If GDB produces an error message for valid input, that is a bug. (Note that if you're cross debugging, the problem may also be somewhere in the connection to the target.) * If GDB 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 our idea of "an extension" or "support for traditional practice". * If you are an experienced user of debugging tools, your suggestions for improvement of GDB are welcome in any case.  File: gdb.info, Node: Bug Reporting, Prev: Bug Criteria, Up: GDB Bugs How to report bugs ================== A number of companies and individuals offer support for GNU products. If you obtained GDB from a support organization, we recommend you contact that organization first. You can find contact information for many support companies and individuals in the file `etc/SERVICE' in the GNU Emacs distribution. In any event, we also recommend that you send bug reports for GDB to this addresses: bug-gdb@prep.ai.mit.edu *Do not send bug reports to `info-gdb', or to `help-gdb', or to any newsgroups.* Most users of GDB do not want to receive bug reports. Those that do have arranged to receive `bug-gdb'. The mailing list `bug-gdb' has a newsgroup `gnu.gdb.bug' which serves as a repeater. The mailing list and the newsgroup carry exactly the same messages. Often people think of posting bug reports to the newsgroup instead of mailing them. This appears to work, but it has one problem which can be crucial: a newsgroup posting often lacks a mail path back to the sender. Thus, if we need to ask for more information, we may be unable to reach you. For this reason, it is better to send bug reports to the mailing list. As a last resort, send bug reports on paper to: GNU Debugger Bugs Free Software Foundation Inc. 59 Temple Place - Suite 330 Boston, MA 02111-1307 USA 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 assume that some details do not matter. Thus, you might assume that the name of the variable you use in an example does not matter. Well, probably it does not, 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 debugger into doing the right thing despite the bug. Play it safe and give a specific, complete example. That is the easiest thing for you to do, and the most helpful. Keep in mind that the purpose of a bug report is to enable us to fix the bug. It may be that the bug has been reported previously, but neither you nor we can know that unless your bug report is complete and self-contained. Sometimes people give a few sketchy facts and ask, "Does this ring a bell?" Those bug reports are useless, and we urge everyone to *refuse to respond to them* except to chide the sender to report bugs properly. To enable us to fix the bug, you should include all these things: * The version of GDB. GDB announces it if you start with no arguments; you can also print it at any time using `show version'. Without this, we will not know whether there is any point in looking for the bug in the current version of GDB. * The type of machine you are using, and the operating system name and version number. 1. What compiler (and its version) was used to compile GDB--e.g. "gcc-2.8.1". * What compiler (and its version) was used to compile the program you are debugging--e.g. "gcc-2.8.1", or "HP92453-01 A.10.32.03 HP C Compiler". For GCC, you can say `gcc --version' to get this information; for other compilers, see the documentation for those compilers. * The command arguments you gave the compiler to compile your example and observe the bug. For example, did you use `-O'? To guarantee you will not omit something important, list them all. A copy of the Makefile (or the output from make) is sufficient. If we were to try to guess the arguments, we would probably guess wrong and then we might not encounter the bug. * A complete input script, and all necessary source files, that will reproduce the bug. * A description of what behavior you observe that you believe is incorrect. For example, "It gets a fatal signal." Of course, if the bug is that GDB gets a fatal signal, then we will certainly notice it. But if the bug is incorrect output, we might not notice unless it is glaringly wrong. You might as well not give us a chance to make a mistake. 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 GDB is out of synch, or you have encountered a bug in the C library on your system. (This has happened!) Your copy might crash and ours would not. If you told us to expect a crash, then when ours fails to crash, we would know that the bug was not happening for us. If you had not told us to expect a crash, then we would not be able to draw any conclusion from our observations. 2. If you wish to suggest changes to the GDB source, send us context diffs. If you even discuss something in the GDB source, refer to it by context, not by line number. The line numbers in our development sources will not match those in your sources. Your line numbers would convey no useful information to us. 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. This is often time consuming and not very useful, because the way we will find the bug is by running a single example under the debugger with breakpoints, not by pure deduction from a series of examples. We recommend that you save your time for something else. Of course, if you can find a simpler example to report *instead* of the original one, that is a convenience for us. Errors in the output will be easier to spot, running under the debugger will take less time, and so on. However, simplification is not vital; if you do not want to do this, report the bug anyway and send us the entire test case you used. * A patch for the bug. A patch for the bug does help us if it is a good one. But do not omit the necessary information, such as the test case, on the assumption that a patch is all we need. We might see problems with your patch and decide to fix the problem another way, or we might not understand it at all. Sometimes with a program as complicated as GDB it is very hard to construct an example that will make the program follow a certain path through the code. If you do not send us the example, we will not be able to construct one, so we will not be able to verify that the bug is fixed. And if we cannot understand what bug you are trying to fix, or why your patch should be an improvement, we will not install it. A test case will help us to understand. * A guess about what the bug is or what it depends on. Such guesses are usually wrong. Even we cannot guess right about such things without first using the debugger to find the facts.  File: gdb.info, Node: Command Line Editing, Next: Using History Interactively, Prev: Formatting Documentation, Up: Top Command Line Editing ******************** This chapter describes the basic features of the GNU command line editing interface. * Menu: * Introduction and Notation:: Notation used in this text. * Readline Interaction:: The minimum set of commands for editing a line. * Readline Init File:: Customizing Readline from a user's view. * Bindable Readline Commands:: A description of most of the Readline commands available for binding * Readline vi Mode:: A short description of how to make Readline behave like the vi editor.  File: gdb.info, Node: Introduction and Notation, Next: Readline Interaction, Up: Command Line Editing Introduction to Line Editing ============================ The following paragraphs describe the notation used to represent keystrokes. The text is read as `Control-K' and describes the character produced when the key is pressed while the Control key is depressed. The text is read as `Meta-K' and describes the character produced when the meta key (if you have one) is depressed, and the key is pressed. If you do not have a meta key, the identical keystroke can be generated by typing first, and then typing . Either process is known as "metafying" the key. The text is read as `Meta-Control-k' and describes the character produced by "metafying" . In addition, several keys have their own names. Specifically, , , , , , and all stand for themselves when seen in this text, or in an init file (*note Readline Init File::.).  File: gdb.info, Node: Readline Interaction, Next: Readline Init File, 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 . You do not have to be at the end of the line to press ; 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. * Searching:: Searching through previous lines.  File: gdb.info, Node: Readline Bare Essentials, Next: Readline Movement Commands, Up: Readline Interaction 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 your erase character 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 to move the cursor to the left, and then correct your mistake. Afterwards, you can move the cursor to the right with . When you add text in the middle of a line, you will notice that characters to the right of the cursor are `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 are `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. Move back one character. Move forward one character. Delete the character to the left of the cursor. Delete the character underneath the cursor. Printing characters Insert the character into the line at the cursor. Undo the last editing command. You can undo all the way back to an empty line.  File: gdb.info, Node: Readline Movement Commands, Next: Readline Killing Commands, Prev: Readline Bare Essentials, Up: Readline Interaction 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 , , , and . Here are some commands for moving more rapidly about the line. Move to the start of the line. Move to the end of the line. Move forward a word, where a word is composed of letters and digits. Move backward a word. Clear the screen, reprinting the current line at the top. Notice how moves forward a character, while moves forward a word. It is a loose convention that control keystrokes operate on characters while meta keystrokes operate on words.  File: gdb.info, Node: Readline Killing Commands, Next: Readline Arguments, Prev: Readline Movement Commands, Up: Readline Interaction Readline Killing Commands ------------------------- "Killing" text means to delete the text from the line, but to save it away for later use, usually by "yanking" (re-inserting) 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. 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 all. 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. Here is the list of commands for killing text. Kill the text from the current cursor position to the end of the line. Kill from the cursor to the end of the current word, or if between words, to the end of the next word. Kill from the cursor the start of the previous word, or if between words, to the start of the previous word. Kill from the cursor to the previous whitespace. This is different than because the word boundaries differ. Here is how to "yank" the text back into the line. Yanking means to copy the most-recently-killed text from the kill buffer. Yank the most recently killed text back into the buffer at the cursor. Rotate the kill-ring, and yank the new top. You can only do this if the prior command is or .  File: gdb.info, Node: Readline Arguments, Next: Searching, Prev: Readline Killing Commands, Up: Readline Interaction 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' typed 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 command an argument of 10, you could type `M-1 0 C-d'.  File: gdb.info, Node: Searching, Prev: Readline Arguments, Up: Readline Interaction Searching for Commands in the History ------------------------------------- Readline provides commands for searching through the command history for lines containing a specified string. There are two search modes: INCREMENTAL and NON-INCREMENTAL. Incremental searches begin before the user has finished typing the search string. As each character of the search string is typed, Readline displays the next entry from the history matching the string typed so far. An incremental search requires only as many characters as needed to find the desired history entry. The character is used to terminate an incremental search. will also terminate the search. will abort an incremental search and restore the original line. When the search is terminated, the history entry containing the search string becomes the current line. To find other matching entries in the history list, type or as appropriate. This will search backward or forward in the history for the next entry matching the search string typed so far. Any other key sequence bound to a Readline command will terminate the search and execute that command. For instance, a will terminate the search and accept the line, thereby executing the command from the history list. Non-incremental searches read the entire search string before starting to search for matching history lines. The search string may be typed by the user or be part of the contents of the current line.  File: gdb.info, Node: Readline Init File, Next: Bindable Readline Commands, Prev: Readline Interaction, Up: Command Line Editing Readline Init File ================== Although the Readline library comes with a set of `emacs'-like keybindings installed by default, it is possible to use a different set of keybindings. Any user can customize programs that use Readline by putting commands in an "inputrc" file in his home directory. The name of this file is taken from the value of the environment variable `INPUTRC'. If that variable is unset, the default is `~/.inputrc'. When a program which uses the Readline library starts up, the init file is read, and the key bindings 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 File Syntax:: Syntax for the commands in the inputrc file. * Conditional Init Constructs:: Conditional key bindings in the inputrc file. * Sample Init File:: An example inputrc file.  File: gdb.info, Node: Readline Init File Syntax, Next: Conditional Init Constructs, Up: Readline Init File Readline Init File Syntax ------------------------- There are only a few basic constructs allowed in the Readline init file. Blank lines are ignored. Lines beginning with a `#' are comments. Lines beginning with a `$' indicate conditional constructs (*note Conditional Init Constructs::.). Other lines denote variable settings and key bindings. Variable Settings You can modify the run-time behavior of Readline by altering the values of variables in Readline using the `set' command within the init file. Here is how to change from the default Emacs-like key binding to use `vi' line editing commands: set editing-mode vi A great deal of run-time behavior is changeable with the following variables. `bell-style' Controls what happens when Readline wants to ring the terminal bell. If set to `none', Readline never rings the bell. If set to `visible', Readline uses a visible bell if one is available. If set to `audible' (the default), Readline attempts to ring the terminal's bell. `comment-begin' The string to insert at the beginning of the line when the `insert-comment' command is executed. The default value is `"#"'. `completion-ignore-case' If set to `on', Readline performs filename matching and completion in a case-insensitive fashion. The default value is `off'. `completion-query-items' The number of possible completions that determines when the user is asked whether he wants to see the list of possibilities. If the number of possible completions is greater than this value, Readline will ask the user whether or not he wishes to view them; otherwise, they are simply listed. The default limit is `100'. `convert-meta' If set to `on', Readline will convert characters with the eighth bit set to an ASCII key sequence by stripping the eighth bit and prepending an character, converting them to a meta-prefixed key sequence. The default value is `on'. `disable-completion' If set to `On', Readline will inhibit word completion. Completion characters will be inserted into the line as if they had been mapped to `self-insert'. The default is `off'. `editing-mode' The `editing-mode' variable controls which default set of key bindings is used. By default, Readline starts up in Emacs editing mode, where the keystrokes are most similar to Emacs. This variable can be set to either `emacs' or `vi'. `enable-keypad' When set to `on', Readline will try to enable the application keypad when it is called. Some systems need this to enable the arrow keys. The default is `off'. `expand-tilde' If set to `on', tilde expansion is performed when Readline attempts word completion. The default is `off'. `horizontal-scroll-mode' This variable can be set to either `on' or `off'. Setting it to `on' means that the text of the lines being edited will scroll horizontally on a single screen line when they are longer than the width of the screen, instead of wrapping onto a new screen line. By default, this variable is set to `off'. `keymap' Sets Readline's idea of the current keymap for key binding commands. Acceptable `keymap' names are `emacs', `emacs-standard', `emacs-meta', `emacs-ctlx', `vi', `vi-command', and `vi-insert'. `vi' is equivalent to `vi-command'; `emacs' is equivalent to `emacs-standard'. The default value is `emacs'. The value of the `editing-mode' variable also affects the default keymap. `mark-directories' If set to `on', completed directory names have a slash appended. The default is `on'. `mark-modified-lines' This variable, when set to `on', causes Readline to display an asterisk (`*') at the start of history lines which have been modified. This variable is `off' by default. `input-meta' If set to `on', Readline will enable eight-bit input (it will not strip the eighth bit from the characters it reads), regardless of what the terminal claims it can support. The default value is `off'. The name `meta-flag' is a synonym for this variable. `output-meta' If set to `on', Readline will display characters with the eighth bit set directly rather than as a meta-prefixed escape sequence. The default is `off'. `print-completions-horizontally' If set to `on', Readline will display completions with matches sorted horizontally in alphabetical order, rather than down the screen. The default is `off'. `show-all-if-ambiguous' This alters the default behavior of the completion functions. If set to `on', words which have more than one possible completion cause the matches to be listed immediately instead of ringing the bell. The default value is `off'. `visible-stats' If set to `on', a character denoting a file's type is appended to the filename when listing possible completions. The default is `off'. Key Bindings The syntax for controlling key bindings in the init file is simple. First you have to know the name of the command that you want to change. The following sections contain tables of the command name, the default keybinding, if any, 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 init 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, is bound to the function `universal-argument', and 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, by placing the key sequence in double quotes. Some GNU Emacs style key escapes can be used, as in the following example, but the special character names are not recognized. "\C-u": universal-argument "\C-x\C-r": re-read-init-file "\e[11~": "Function Key 1" In the above example, is bound to the function `universal-argument' (just as it was in the first example), ` ' is bound to the function `re-read-init-file', and ` <[> <1> <1> <~>' is bound to insert the text `Function Key 1'. The following GNU Emacs style escape sequences are available when specifying key sequences: `\C-' control prefix `\M-' meta prefix `\e' an escape character `\\' backslash `\"' <"> `\'' <'> In addition to the GNU Emacs style escape sequences, a second set of backslash escapes is available: `\a' alert (bell) `\b' backspace `\d' delete `\f' form feed `\n' newline `\r' carriage return `\t' horizontal tab `\v' vertical tab `\NNN' the character whose ASCII code is the octal value NNN (one to three digits) `\xNNN' the character whose ASCII code is the hexadecimal value NNN (one to three digits) When entering the text of a macro, single or double quotes must be used to indicate a macro definition. Unquoted text is assumed to be a function name. In the macro body, the backslash escapes described above are expanded. Backslash will quote any other character in the macro text, including `"' and `''. For example, the following binding will make `C-x \' insert a single `\' into the line: "\C-x\\": "\\"  File: gdb.info, Node: Conditional Init Constructs, Next: Sample Init File, Prev: Readline Init File Syntax, Up: Readline Init File Conditional Init Constructs --------------------------- Readline implements a facility similar in spirit to the conditional compilation features of the C preprocessor which allows key bindings and variable settings to be performed as the result of tests. There are four parser directives used. `$if' The `$if' construct allows bindings to be made based on the editing mode, the terminal being used, or the application using Readline. The text of the test extends to the end of the line; no characters are required to isolate it. `mode' The `mode=' form of the `$if' directive is used to test whether Readline is in `emacs' or `vi' mode. This may be used in conjunction with the `set keymap' command, for instance, to set bindings in the `emacs-standard' and `emacs-ctlx' keymaps only if Readline is starting out in `emacs' mode. `term' The `term=' form may be used to include terminal-specific key bindings, perhaps to bind the key sequences output by the terminal's function keys. The word on the right side of the `=' is tested against both the full name of the terminal and the portion of the terminal name before the first `-'. This allows `sun' to match both `sun' and `sun-cmd', for instance. `application' The APPLICATION construct is used to include application-specific settings. Each program using the Readline library sets the APPLICATION NAME, and you can test for it. This could be used to bind key sequences to functions useful for a specific program. For instance, the following command adds a key sequence that quotes the current or previous word in Bash: $if Bash # Quote the current or previous word "\C-xq": "\eb\"\ef\"" $endif `$endif' This command, as seen in the previous example, terminates an `$if' command. `$else' Commands in this branch of the `$if' directive are executed if the test fails. `$include' This directive takes a single filename as an argument and reads commands and bindings from that file. $include /etc/inputrc  File: gdb.info, Node: Sample Init File, Prev: Conditional Init Constructs, Up: Readline Init File Sample Init File ---------------- Here is an example of an inputrc file. This illustrates key binding, variable assignment, and conditional syntax. # This file controls the behaviour of line input editing for # programs that use the Gnu Readline library. Existing programs # include FTP, Bash, and Gdb. # # You can re-read the inputrc file with C-x C-r. # Lines beginning with '#' are comments. # # First, include any systemwide bindings and variable assignments from # /etc/Inputrc $include /etc/Inputrc # # Set various bindings for emacs mode. set editing-mode emacs $if mode=emacs Meta-Control-h: backward-kill-word Text after the function name is ignored # # Arrow keys in keypad mode # #"\M-OD": backward-char #"\M-OC": forward-char #"\M-OA": previous-history #"\M-OB": next-history # # Arrow keys in ANSI mode # "\M-[D": backward-char "\M-[C": forward-char "\M-[A": previous-history "\M-[B": next-history # # Arrow keys in 8 bit keypad mode # #"\M-\C-OD": backward-char #"\M-\C-OC": forward-char #"\M-\C-OA": previous-history #"\M-\C-OB": next-history # # Arrow keys in 8 bit ANSI mode # #"\M-\C-[D": backward-char #"\M-\C-[C": forward-char #"\M-\C-[A": previous-history #"\M-\C-[B": next-history C-q: quoted-insert $endif # An old-style binding. This happens to be the default. TAB: complete # Macros that are convenient for shell interaction $if Bash # edit the path "\C-xp": "PATH=${PATH}\e\C-e\C-a\ef\C-f" # prepare to type a quoted word -- insert open and close double quotes # and move to just after the open quote "\C-x\"": "\"\"\C-b" # insert a backslash (testing backslash escapes in sequences and macros) "\C-x\\": "\\" # Quote the current or previous word "\C-xq": "\eb\"\ef\"" # Add a binding to refresh the line, which is unbound "\C-xr": redraw-current-line # Edit variable on current line. "\M-\C-v": "\C-a\C-k$\C-y\M-\C-e\C-a\C-y=" $endif # use a visible bell if one is available set bell-style visible # don't strip characters to 7 bits when reading set input-meta on # allow iso-latin1 characters to be inserted rather than converted to # prefix-meta sequences set convert-meta off # display characters with the eighth bit set directly rather than # as meta-prefixed characters set output-meta on # if there are more than 150 possible completions for a word, ask the # user if he wants to see all of them set completion-query-items 150 # For FTP $if Ftp "\C-xg": "get \M-?" "\C-xt": "put \M-?" "\M-.": yank-last-arg $endif  File: gdb.info, Node: Bindable Readline Commands, Next: Readline vi Mode, Prev: Readline Init File, Up: Command Line Editing Bindable Readline Commands ========================== * 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. * Keyboard Macros:: Saving and re-executing typed characters * Miscellaneous Commands:: Other miscellaneous commands. This section describes Readline commands that may be bound to key sequences.  File: gdb.info, Node: Commands For Moving, Next: Commands For History, Up: Bindable Readline Commands 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. Words are composed of letters and digits. `backward-word (M-b)' Move back to the start of this, or the previous, word. Words are composed of letters and digits. `clear-screen (C-l)' Clear the screen and redraw the current line, leaving the current line at the top of the screen. `redraw-current-line ()' Refresh the current line. By default, this is unbound.  File: gdb.info, Node: Commands For History, Next: Commands For Text, Prev: Commands For Moving, Up: Bindable Readline Commands 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 currently being entered. `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. This is an incremental search. `non-incremental-reverse-search-history (M-p)' Search backward starting at the current line and moving `up' through the history as necessary using a non-incremental search for a string supplied by the user. `non-incremental-forward-search-history (M-n)' Search forward starting at the current line and moving `down' through the the history as necessary using a non-incremental search for a string supplied by the user. `history-search-forward ()' Search forward through the history for the string of characters between the start of the current line and the current cursor position (the POINT). This is a non-incremental search. By default, this command is unbound. `history-search-backward ()' Search backward through the history for the string of characters between the start of the current line and the point. This is a non-incremental search. By default, this command is unbound. `yank-nth-arg (M-C-y)' Insert the first argument to the previous command (usually the second word on the previous line). With an argument N, insert the Nth word from the previous command (the words in the previous command begin with word 0). A negative argument inserts the Nth word from the end of the previous command. `yank-last-arg (M-., M-_)' Insert last argument to the previous command (the last word of the previous history entry). With an argument, behave exactly like `yank-nth-arg'. Successive calls to `yank-last-arg' move back through the history list, inserting the last argument of each line in turn.  File: gdb.info, Node: Commands For Text, Next: Commands For Killing, Prev: Commands For History, Up: Bindable Readline Commands Commands For Changing Text -------------------------- `delete-char (C-d)' Delete the character under the cursor. If the cursor is at the beginning of the line, there are no characters in the line, and the last character typed was not bound to `delete-char', then return `EOF'. `backward-delete-char (Rubout)' Delete the character behind the cursor. A numeric argument means to kill the characters instead of deleting them. `quoted-insert (C-q, C-v)' Add the next character typed to the line verbatim. This is how to insert key sequences like , 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 the cursor forward over the character at the cursor, moving the cursor forward as well. If the insertion point is at the end of the line, then this transposes the last two characters of the line. Negative arguments 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, uppercase the previous word, but do not move the cursor. `downcase-word (M-l)' Lowercase the current (or following) word. With a negative argument, lowercase the previous word, but do not move the cursor. `capitalize-word (M-c)' Capitalize the current (or following) word. With a negative argument, capitalize the previous word, but do not move the cursor.  File: gdb.info, Node: Commands For Killing, Next: Numeric Arguments, Prev: Commands For Text, Up: Bindable Readline Commands Killing And Yanking ------------------- `kill-line (C-k)' Kill the text from the current cursor position to the end of the line. `backward-kill-line (C-x Rubout)' Kill backward to the beginning of the line. `unix-line-discard (C-u)' Kill backward from the cursor to the beginning of the current line. The killed text is saved on the kill-ring. `kill-whole-line ()' Kill all characters on the current line, no matter where the cursor is. By default, this is 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. Word boundaries are the same as `forward-word'. `backward-kill-word (M-DEL)' Kill the word behind the cursor. Word boundaries are the same as `backward-word'. `unix-word-rubout (C-w)' Kill the word behind the cursor, using white space as a word boundary. The killed text is saved on the kill-ring. `delete-horizontal-space ()' Delete all spaces and tabs around point. By default, this is unbound. `kill-region ()' Kill the text between the point and the *mark* (saved cursor position). This text is referred to as the REGION. By default, this command is unbound. `copy-region-as-kill ()' Copy the text in the region to the kill buffer, so it can be yanked right away. By default, this command is unbound. `copy-backward-word ()' Copy the word before point to the kill buffer. The word boundaries are the same as `backward-word'. By default, this command is unbound. `copy-forward-word ()' Copy the word following point to the kill buffer. The word boundaries are the same as `forward-word'. By default, this command is unbound. `yank (C-y)' Yank the top of the kill ring into the buffer at the current cursor position. `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: gdb.info, Node: Numeric Arguments, Next: Commands For Completion, Prev: Commands For Killing, Up: Bindable Readline Commands Specifying Numeric Arguments ---------------------------- `digit-argument (M-0, M-1, ... M--)' Add this digit to the argument already accumulating, or start a new argument. starts a negative argument. `universal-argument ()' This is another way to specify an argument. If this command is followed by one or more digits, optionally with a leading minus sign, those digits define the argument. If the command is followed by digits, executing `universal-argument' again ends the numeric argument, but is otherwise ignored. As a special case, if this command is immediately followed by a character that is neither a digit or minus sign, the argument count for the next command is multiplied by four. The argument count is initially one, so executing this function the first time makes the argument count four, a second time makes the argument count sixteen, and so on. By default, this is not bound to a key.