Linux Cubed Series 2: Applications

home *** CD-ROM | disk | FTP | other *** search

/ Linux Cubed Series 2: Applications / Linux Cubed Series 2 - Applications.iso / editors / emacs / emacs-19.000 / emacs-19 / usr / local / info / emacs-20 < prev next >

Wrap

GNU Info File | 1995-09-11 | 46.2 KB | 1,176 lines

This is Info file ../info/emacs, produced by Makeinfo-1.55 from the input file emacs.texi. File: emacs, Node: Checklist, Next: Sending Patches, Prev: Understanding Bug Reporting, Up: Bugs Checklist for Bug Reports ------------------------- The best way to send a bug report is to mail it electronically to the Emacs maintainers at `bug-gnu-emacs@prep.ai.mit.edu'. (If you want to suggest a change as an improvement, use the same address.) If you'd like to read the bug reports, you can find them on the newsgroup `gnu.emacs.bug'; keep in mind, however, that as a spectator you should not criticize anything about what you see there. The purpose of bug reports is to give information to the Emacs maintainers. Spectators are welcome only as long as they do not interfere with this. In particular, some bug reports contain large amounts of data; spectators should not complain about this. Please do not post bug reports using netnews; mail is more reliable than netnews about reporting your correct address, which we may need in order to ask you for more information. If you can't send electronic mail, then mail the bug report on paper or machine-readable media to this address: GNU Emacs Bugs Free Software Foundation 59 Temple Place, Suite 330 Boston, MA 02111-1307 USA We do not promise to fix the bug; but if the bug is serious, or ugly, or easy to fix, chances are we will want to. To enable maintainers to investigate a bug, your report should include all these things: * The version number of Emacs. Without this, we won't know whether there is any point in looking for the bug in the current version of GNU Emacs. You can get the version number by typing `M-x emacs-version RET'. If that command does not work, you probably have something other than GNU Emacs, so you will have to report the bug somewhere else. * The type of machine you are using, and the operating system name and version number. `M-x emacs-version RET' provides this information too. Copy its output from the `*Messages*' buffer, so that you get it all and get it accurately. * The operands given to the `configure' command when Emacs was installed. * A complete list of any modifications you have made to the Emacs source. (We may not have time to investigate the bug unless it happens in an unmodified Emacs. But if you've made modifications and you don't tell us, you are sending us on a wild goose chase.) Be precise about these changes. A description in English is not enough--send a context diff for them. Adding files of your own, or porting to another machine, is a modification of the source. * Details of any other deviations from the standard procedure for installing GNU Emacs. * The complete text of any files needed to reproduce the bug. If you can tell us a way to cause the problem without visiting any files, please do so. This makes it much easier to debug. If you do need files, make sure you arrange for us to see their exact contents. For example, it can often matter whether there are spaces at the ends of lines, or a newline after the last line in the buffer (nothing ought to care whether the last line is terminated, but try telling the bugs that). * The precise commands we need to type to reproduce the bug. The easy way to record the input to Emacs precisely is to to write a dribble file. To start the file, execute the Lisp expression (open-dribble-file "~/dribble") using `M-ESC' or from the `*scratch*' buffer just after starting Emacs. From then on, Emacs copies all your input to the specified dribble file until the Emacs process is killed. * For possible display bugs, the terminal type (the value of environment variable `TERM'), the complete termcap entry for the terminal from `/etc/termcap' (since that file is not identical on all machines), and the output that Emacs actually sent to the terminal. The way to collect the terminal output is to execute the Lisp expression (open-termscript "~/termscript") using `M-ESC' or from the `*scratch*' buffer just after starting Emacs. From then on, Emacs copies all terminal output to the specified termscript file as well, until the Emacs process is killed. If the problem happens when Emacs starts up, put this expression into your `.emacs' file so that the termscript file will be open when Emacs displays the screen for the first time. Be warned: it is often difficult, and sometimes impossible, to fix a terminal-dependent bug without access to a terminal of the type that stimulates the bug. * A description of what behavior you observe that you believe is incorrect. For example, "The Emacs process gets a fatal signal," or, "The resulting text is as follows, which I think is wrong." Of course, if the bug is that Emacs gets a fatal signal, then one can't miss it. But if the bug is incorrect text, the maintainer might fail to notice what is wrong. Why leave it to chance? 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 source is out of sync, or you have encountered a bug in the C library on your system. (This has happened!) Your copy might crash and the copy here might not. If you *said* to expect a crash, then when Emacs 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. * If the manifestation of the bug is an Emacs error message, it is important to report the precise text of the error message, and a backtrace showing how the Lisp program in Emacs arrived at the error. To get the error message text accurately, copy it from the `*Messages*' buffer into the bug report. Copy all of it, not just part. To make a backtrace for the error, evaluate the Lisp expression `(setq debug-on-error t)' before the error happens (that is to say, you must execute that expression and then make the bug happen). This causes the error to run the Lisp debugger, which shows you a backtrace. Copy the text of the debugger's backtrace into the bug report. This use of the debugger is possible only if you know how to make the bug happen again. If you can't make it happen again, at least copy the whole error message. * Check whether any programs you have loaded into the Lisp world, including your `.emacs' file, set any variables that may affect the functioning of Emacs. Also, see whether the problem happens in a freshly started Emacs without loading your `.emacs' file (start Emacs with the `-q' switch to prevent loading the init file.) If the problem does *not* occur then, you must report the precise contents of any programs that you must load into the Lisp world in order to cause the problem to occur. * If the problem does depend on an init file or other Lisp programs that are not part of the standard Emacs system, then you should make sure it is not a bug in those programs by complaining to their maintainers first. After they verify that they are using Emacs in a way that is supposed to work, they should report the bug. * If you wish to mention something in the GNU Emacs source, show the line of code with a few lines of context. Don't just give a line number. The line numbers in the development sources don't match those in your sources. It would take extra work for the maintainers to determine what code is in your version at a given line number, and we could not be certain. * Additional information from a C debugger such as GDB might enable someone to find a problem on a machine which he does not have available. If you don't know how to use GDB, please read the GDB manual--it is not very long, and using GDB is easy. You can find the GDB distribution, including the GDB manual in online form, in most of the same places you can find the Emacs distribution. However, you need to think when you collect the additional information if you want it to show what causes the bug. For example, many people send just a backtrace, but that is not very useful by itself. A simple backtrace with arguments often conveys little about what is happening inside GNU Emacs, because most of the arguments listed in the backtrace are pointers to Lisp objects. The numeric values of these pointers have no significance whatever; all that matters is the contents of the objects they point to (and most of the contents are themselves pointers). To provide useful information, you need to show the values of Lisp objects in Lisp notation. Do this for each variable which is a Lisp object, in several stack frames near the bottom of the stack. Look at the source to see which variables are Lisp objects, because the debugger thinks of them as integers. To show a variable's value in Lisp syntax, first print its value, then use the user-defined GDB command `pr' to print the Lisp object in Lisp syntax. (If you must use another debugger, call the function `debug_print' with the object as an argument.) The `pr' command is defined by the file `.gdbinit' in the `src' subdirectory, and it works only if you are debugging a running process (not with a core dump). To make Lisp errors stop Emacs and return to GDB, put a breakpoint at `Fsignal'. To find out which Lisp functions are running, using GDB, move up the stack, and each time you get to a frame for the function `Ffuncall', type these GDB commands: p *args pr To print the first argument that the function received, use these commands: p args[1] pr You can print the other arguments likewise. The argument `nargs' of `Ffuncall' says how many arguments `Ffuncall' received; these include the Lisp function itself and the arguments for that function. * If the symptom of the bug is that Emacs fails to respond, don't assume Emacs is "hung"--it may instead be in an infinite loop. To find out which, make the problem happen under GDB and stop Emacs once it is not responding. (If Emacs is using X Windows directly, you can stop Emacs by typing `C-c' at the GDB job.) Then try stepping with `step'. If Emacs is hung, the `step' command won't return. If it is looping, `step' will return. If this shows Emacs is hung in a system call, stop it again and examine the arguments of the call. In your bug report, state exactly where in the source the system call is, and what the arguments are. If Emacs is in an infinite loop, please determine where the loop starts and ends. The easiest way to do this is to use the GDB command `finish'. Each time you use it, Emacs resumes execution until it exits one stack frame. Keep typing `finish' until it doesn't return--that means the infinite loop is in the stack frame which you just tried to finish. Stop Emacs again, and use `finish' repeatedly again until you get *back to* that frame. Then use `next' to step through that frame. By stepping, you will see where the loop starts and ends. Also please examine the data being used in the loop and try to determine why the loop does not exit when it should. Include all of this information in your bug report. Here are some things that are not necessary in a bug report: * A description of the envelope of the bug--this is not necessary for a reproducible 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. You might as well save time by not searching for additional examples. Of course, 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. However, simplification is not vital; if you can't do this or don't have time to try, please report the bug with your original test case. * A system call trace of Emacs execution. System call traces are very useful for certain special kinds of debugging, but in most cases they give little useful information. It is therefore strange that many people seem to think that *the* way to report information about a crash is to send a system call trace. In most programs, a backtrace is normally far, far more informative than a system call trace. Even in Emacs, a simple backtrace is generally more informative, though to give full information you should supplement the backtrace by displaying variable values and printing them as Lisp objects with `pr' (see above). * A patch for the bug. A patch for the bug is useful if it is a good one. But don't omit the other information that a bug report needs, such as the test case, on the assumption that a patch is sufficient. We might see problems with your patch and decide to fix the problem another way, or we might not understand it at all. And if we can't understand what bug you are trying to fix, or why your patch should be an improvement, we mustn't install it. *Note Sending Patches::, for guidelines on how to make it easy for us to understand and install your patches. * A guess about what the bug is or what it depends on. Such guesses are usually wrong. Even experts can't guess right about such things without first using the debugger to find the facts. File: emacs, Node: Sending Patches, Prev: Checklist, Up: Bugs Sending Patches for GNU Emacs ----------------------------- If you would like to write bug fixes or improvements for GNU Emacs, that is very helpful. When you send your changes, please follow these guidelines to make it easy for the maintainers to use them. If you don't follow these guidelines, your information might still be useful, but using it will take extra work. Maintaining GNU Emacs 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. (Referring to a bug report is not as good as including it, because then we will have to look it up, and we have probably already deleted it if we've already fixed 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 correct, we might have trouble understanding 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. If you send them all jumbled together in a single set of diffs, we have to do extra work to disentangle them--to figure out which parts of the change serve which purpose. If we don't have time for this, we might have to ignore your changes entirely. If you send each change as soon as you have written it, with its own explanation, then two changes never get tangled up, and we can consider each one properly without any extra work to disentangle them. * Send each change as soon as that change is finished. Sometimes people think they are helping us by accumulating many changes to send them all together. As explained above, this is absolutely the worst thing you could do. Since you should send each change separately, you might as well send it right away. That gives us the option of installing it immediately if it is important. * Use `diff -c' to make your diffs. Diffs without context are hard to install reliably. More than that, they are hard to study; we must always study a patch to decide whether we want to install it. Unidiff format is better than contextless diffs, but not as easy to read as `-c' format. If you have GNU diff, use `diff -c -F'^[_a-zA-Z0-9$]+ *('' when making diffs of C code. This shows the name of the function that each change occurs in. * Write the change log entries for your changes. This is both to save us the extra work of writing them, and to help explain your changes so we can understand them. 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. On the other hand, once you have shown people where to find the change, you need not explain its purpose in the change log. 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 put the explanation in comments in the code. It will be more useful there. Please read the `ChangeLog' files in the `src' and `lisp' directories to see what sorts of information to put in, and to learn the style that we use. If you would like your name to appear in the header line, showing who made the change, send us the header line. *Note Change Log::. * When you write the fix, keep in mind that we can't install a change that would break other systems. Please think about what effect your change will have if compiled on another type of system. Sometimes people send fixes that *might* be an improvement in general--but it is hard to be sure of this. It's hard to install such changes because we have to study them very carefully. Of course, a good explanation of the reasoning by which you concluded the change was correct can help convince us. The safest changes are changes to the configuration files for a particular machine. These are safe because they can't create new bugs on other machines. Please help us keep up with the workload by designing the patch in a form that is clearly safe to install. File: emacs, Node: Service, Next: Command Arguments, Prev: Bugs, Up: Top How To Get Help with GNU Emacs ============================== If you need help installing, using or changing GNU Emacs, there are two ways to find it: * Send a message to the mailing list `help-gnu-emacs@prep.ai.mit.edu', or post your request on newsgroup `gnu.emacs.help'. (This mailing list and newsgroup interconnect, so it does not matter which one you use.) * Look in the service directory for someone who might help you for a fee. The service directory is found in the file named `etc/SERVICE' in the Emacs distribution. File: emacs, Node: Command Arguments, Next: Antinews, Prev: Service, Up: Top Command Line Arguments ********************** GNU Emacs supports command line arguments to request various actions when invoking Emacs. These are for compatibility with other editors and for sophisticated activities. We don't recommend using them for ordinary editing. Arguments starting with `-' are "options". Other arguments specify files to visit. Emacs visits the specified files while it starts up. The last file name on your command line becomes the current buffer; the other files are also present in other buffers. You can use options to specify various other things, such as the size and position of the X window Emacs uses, its colors, and so on. A few options support advanced usage, such as running Lisp functions on files in batch mode. The sections of this chapter describe the available options, arranged according to their purpose. There are two ways of writing options: the short forms that start with a single `-', and the long forms that start with `--'. For example, `-d' is a short form and `--display' is the corresponding long form. The long forms with `--' are easier to remember, but longer to type. However, you don't have to spell out the whole option name; any unambiguous abbreviation is enough. When a long option takes an argument, you can use either a space or an equal sign to separate the option name and the argument. Thus, you can write either `--display sugar-bombs:0.0' or `--display=sugar-bombs:0.0'. We recommend an equal sign because it makes the relationship clearer, and the tables below always show an equal sign. Most options specify how to initialize Emacs, or set parameters for the Emacs session. We call them "initial options". A few options specify things to do: for example, load libraries, call functions, or exit Emacs. These are called "action options". These and file names together are called "action arguments". Emacs processes all the action arguments in the order they are written. * Menu: * Action Arguments:: Arguments to visit files, load libraries, and call functions. * Initial Options:: Arguments that take effect while starting Emacs. * Command Example:: Examples of using command line arguments. * Resume Arguments:: Specifying arguments when you resume a running Emacs. * Environment:: Environment variables that Emacs uses. * Display X:: Changing the default display and using remote login. * Font X:: Choosing a font for text, under X. * Colors X:: Choosing colors, under X. * Window Size X:: Start-up window size, under X. * Borders X:: Internal and external borders, under X. * Icons X:: Choosing what sort of icon to use, under X. * Resources X:: Advanced use of classes and resources, under X. * Lucid Resources:: X resources for Lucid menus. * Motif Resources:: X resources for Motif menus. File: emacs, Node: Action Arguments, Next: Initial Options, Up: Command Arguments Action Arguments ================ Here is a table of the action arguments and options: `FILE' Visit FILE using `find-file'. *Note Visiting::. `+LINENUM FILE' Visit FILE using `find-file', then go to line number LINENUM in it. `-l FILE' `--load=FILE' Load a file FILE of Lisp code with the function `load'. *Note Lisp Libraries::. `-f FUNCTION' `--funcall=FUNCTION' Call Lisp function FUNCTION with no arguments. `--insert=FILE' Insert the contents of FILE into the current buffer. This is like what `M-x insert-file' does. *Note Misc File Ops::. `--kill' Exit from Emacs without asking for confirmation. The init file can access the values of the action arguments as the elements of a list in the variable `command-line-args'. The init file can override the normal processing of the action arguments, or define new ones, by reading and setting this variable. File: emacs, Node: Initial Options, Next: Command Example, Prev: Action Arguments, Up: Command Arguments Initial Options =============== The initial options specify parameter for the Emacs session. This section describes the more general initial options; some other options specifically related to X Windows appear in the following sections. Some initial options affect the loading of init files. The normal actions of Emacs are to first load `site-start.el' if it exists, then your own init file `~/.emacs' if it exists, and finally `default.el' if it exists; certain options prevent loading of some of these files or substitute other files for them. `-t DEVICE' `--terminal=DEVICE' Use DEVICE as the device for terminal input and output. `-d DISPLAY' `--display=DISPLAY' Use the X Window System and use the display named DISPLAY to open the initial Emacs frame. `-nw' `--no-windows' Don't communicate directly with X, disregarding the `DISPLAY' environment variable even if it is set. `-batch' `--batch' Run Emacs in "batch mode", which means that the text being edited is not displayed and the standard terminal interrupt characters such as `C-z' and `C-c' continue to have their normal effect. Emacs in batch mode outputs to `stderr' only what would normally be printed in the echo area under program control. Batch mode is used for running programs written in Emacs Lisp from shell scripts, makefiles, and so on. Normally the `-l' option or `-f' option will be used as well, to invoke a Lisp program to do the batch processing. `-batch' implies `-q' (do not load an init file). It also causes Emacs to kill itself after all command options have been processed. In addition, auto-saving is not done except in buffers for which it has been explicitly requested. `-q' `--no-init-file' Do not load your Emacs init file `~/.emacs', or `default.el' either. `--no-site-file' Do not load `site-start.el'. The options `-q', `-u' and `-batch' have no effect on the loading of this file--this is the only option that blocks it. `-u USER' `--user=USER' Load USER's Emacs init file `~USER/.emacs' instead of your own. `--debug-init' Enable the Emacs Lisp debugger for errors in the init file. File: emacs, Node: Command Example, Next: Resume Arguments, Prev: Initial Options, Up: Command Arguments Command Argument Example ======================== Here is an example of using Emacs with arguments and options. It assumes you have a Lisp program file called `hack-c.el' which, when loaded, performs some useful operation on current buffer, expected to be a C program. emacs -batch foo.c -l hack-c -f save-buffer >& log This says to visit `foo.c', load `hack-c.el' (which makes changes in the visited file), save `foo.c' (note that `save-buffer' is the function that `C-x C-s' is bound to), and then exit back to the shell (because of `-batch'). `-batch' also guarantees there will be no problem redirecting output to `log', because Emacs will not assume that it has a display terminal to work with. File: emacs, Node: Resume Arguments, Next: Environment, Prev: Command Example, Up: Command Arguments Resuming Emacs with Arguments ============================= You can specify action arguments for Emacs when you resume it after a suspension. To prepare for this, put the following code in your `.emacs' file (*note Hooks::.): (add-hook 'suspend-hook 'resume-suspend-hook) As further preparation, you must execute the shell script `emacs.csh' (if you use csh as your shell) or `emacs.bash' (if you use bash as your shell). These scripts define an alias named `edit', which will resume Emacs giving it new command line arguments such as files to visit. Only action arguments work properly when you resume Emacs. Initial arguments are not recognized--it's too late to execute them anyway. Note that resuming Emacs (with or without arguments) must be done from within the shell that is the parent of the Emacs job. This is why `edit' is an alias rather than a program or a shell script. It is not possible to implement a resumption command that could be run from other subjobs of the shell; no way to define a command that could be made the value of `EDITOR', for example. Therefore, this feature does not take the place of the Emacs Server feature (*note Emacs Server::.). The aliases use the Emacs Server feature if you appear to have a server Emacs running. However, they cannot determine this with complete accuracy. They may think that a server is still running when in actuality you have killed that Emacs, because the file `/tmp/.esrv...' still exists. If this happens, find that file and delete it. File: emacs, Node: Environment, Next: Display X, Prev: Resume Arguments, Up: Command Arguments Environment Variables ===================== This appendix describes how Emacs uses environment variables. An environment variable is a string passed from the operating system to Emacs, and the collection of environment variables is known as the environment. Environment variable names are case sensitive and it is conventional to use upper case letters only. Because environment variables come from the operating system there is no general way to set them; it depends on the operating system and especially the shell that you are using. For example, here's how to set the environment variable `ORGANIZATION' to `not very much' using bash: export ORGANIZATION="not very much" and here's how to do it in csh or tcsh: setenv ORGANIZATION "not very much" When Emacs is set-up to use the X windowing system, it inherits the use of a large number of environment variables from the X library. See the X documentation for more information. * Menu: * General Variables:: Environment variables that all versions of Emacs use. * Misc Variables:: Certain system specific variables. File: emacs, Node: General Variables, Next: Misc Variables, Up: Environment General Variables ----------------- `AUTHORCOPY' The name of a file used to archive news articles posted with the GNUS package. `CDPATH' Used by the `cd' command. `DOMAINNAME' The name of the internet domain that the machine running Emacs is located in. Used by the GNUS package. `EMACSDATA' Used to initialize the variable `data-directory' used to locate the architecture-independent files that come with Emacs. Setting this variable overrides the setting in `paths.h' when Emacs was built. `EMACSLOADPATH' A colon-separated list of directories from which to load Emacs Lisp files. Setting this variable overrides the setting in `paths.h' when Emacs was built. `EMACSLOCKDIR' The directory that Emacs places lock files--files used to protect users from editing the same files simultaneously. Setting this variable overrides the setting in `paths.h' when Emacs was built. `EMACSPATH' The location of Emacs-specific binaries. Setting this variable overrides the setting in `paths.h' when Emacs was built. `ESHELL' Used for shell-mode to override the `SHELL' environment variable. `HISTFILE' The name of the file that shell commands are saved in between logins. This variable defaults to `~/.history' if you use (t)csh as shell, to `~/.bash_history' if you use bash, to `~/.sh_history' if you use ksh, and to `~/.history' otherwise. `HOME' The location of the user's files in the directory tree; used for expansion of file names starting with a tilde (`~'). On MS-DOS, it defaults to the directory from which Emacs was started, with `/bin' removed from the end if it was present. `HOSTNAME' The name of the machine that Emacs is running on. `INCPATH' A colon-separated list of directories. Used by the `complete' package to search for files. `INFOPATH' A colon separated list of directories holding info files. Setting this variable overrides the setting in `paths.el' when Emacs was built. `LOGNAME' The user's login name. See also `USER'. `MAIL' The name of the user's system mail box. `MAILRC' Name of file containing mail aliases. This defaults to `~/.mailrc'. `MH' Name of setup file for the mh system. This defaults to `~/.mh_profile'. `NAME' The real-world name of the user. `NNTPSERVER' The name of the news server. Used by the mh and GNUS packages. `ORGANIZATION' The name of the organization to which you belong. Used for setting the `Organization:' header in your posts from the GNUS package. `PATH' A colon-separated list of directories in which executables reside. (On MS-DOS, it is semicolon-separated instead.) This variable is used to set the Emacs Lisp variable `exec-path' which you should consider to use instead. `PWD' If set, this should be the default directory when Emacs was started. `REPLYTO' If set, this specifies an initial value for the variable `mail-default-reply-to'. *Note Mail Headers::. `SAVEDIR' The name of a directory in which news articles are saved by default. Used by the GNUS package. `SHELL' The name of an interpreter used to parse and execute programs run from inside Emacs. `TERM' The name of the terminal that Emacs is running on. The variable must be set unless Emacs is run in batch mode. On MS-DOS, it defaults to `internal', which specifies a built-in terminal emulation that handles the machine's own display. `TERMCAP' The name of the termcap library file describing how to program the terminal specified by the `TERM' variable. This defaults to `/etc/termcap'. `TMPDIR' Used by the Emerge package as a prefix for temporary files. `TZ' This specifies the current time zone and possibly also daylight savings information. On MS-DOS, the default is based on country code; see the file `msdos.c' for details. `USER' The user's login name. See also `LOGNAME'. On MS-DOS, this defaults to `root'. `VERSION_CONTROL' Used to initialize the `version-control' variable (*note Backup Names::.). File: emacs, Node: Misc Variables, Prev: General Variables, Up: Environment Misc Variables -------------- These variables are used only on particular configurations: `COMSPEC' On MS-DOS, the name of the command interpreter to use. This is used to make a default value for the `SHELL' environment variable. `NAME' On MS-DOS, this variable defaults to the value of the `USER' variable. `TEMP' `TMP' On MS-DOS, these specify the name of the directory for storing temporary files in. `WINDOW_GFX' Used when initializing the Sun windows system. File: emacs, Node: Display X, Next: Font X, Prev: Environment, Up: Command Arguments Specifying the Display Name =========================== The environment variable `DISPLAY' tells all X clients, including Emacs, where to display their windows. Its value is set up by default in ordinary circumstances, when you start an X server and run jobs locally. Occasionally you may need to specify the display yourself; for example, if you do a remote login and want to run a client program remotely, displaying on your local screen. With Emacs, the main reason people change the default display is to let them log into another system, run Emacs on that system, but have the window displayed at their local terminal. You might need to use login to another system because the files you want to edit are there, or because the Emacs executable file you want to run is there. The syntax of the `DISPLAY' environment variable is `HOST:DISPLAY.SCREEN', where HOST is the host name of the X Window System server machine, DISPLAY is an arbitrarily-assigned number that distinguishes your server (X terminal) from other servers on the same machine, and SCREEN is a rarely-used field that allows an X server to control multiple terminal screens. The period and the SCREEN field are optional. If included, SCREEN is usually zero. For example, if your host is named `glasperle' and your server is the first (or perhaps the only) server listed in the configuration, your `DISPLAY' is `glasperle:0.0'. You can specify the display name explicitly when you run Emacs, either by changing the `DISPLAY' variable, or with the option `-d DISPLAY' or `--display=DISPLAY'. Here is an example: emacs --display=glasperle:0 & You can inhibit the direct use of X with the `-nw' option. This is also an initial option. It tells Emacs to display using ordinary ASCII on its controlling terminal. Sometimes, security arrangements prevent a program on a remote system from displaying on your local system. In this case, trying to run Emacs produces messages like this: Xlib: connection to "glasperle:0.0" refused by server You might be able to overcome this problem by using the `xhost' command on the local system to give permission for access from your remote machine. File: emacs, Node: Font X, Next: Colors X, Prev: Display X, Up: Command Arguments Font Specification Options ========================== By default, Emacs displays text in the font named `9x15', which makes each character nine pixels wide and fifteen pixels high. You can specify a different font on your command line through the option `-fn NAME'. `-fn NAME' Use font NAME as the default font. `--font=NAME' `--font' is an alias for `-fn'. Under X, each font has a long name which consists of eleven words or numbers, separated by dashes. Some fonts also have shorter nicknames--`9x15' is such a nickname. You can use either kind of name. You can use wild card patterns for the font name; then Emacs lets X choose one of the fonts that match the pattern. Here is an example, which happens to specify the font whose nickname is `6x13': emacs -fn "-misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1" & You can also specify the font in your `.Xdefaults' file: emacs.font: -misc-fixed-medium-r-semicondensed--13-*-*-*-c-60-iso8859-1 A long font name has the following form: -MAKER-FAMILY-WEIGHT-SLANT-WIDTHTYPE-STYLE... ...-PIXELS-HEIGHT-HORIZ-VERT-SPACING-WIDTH-CHARSET FAMILY This is the name of the font family-for example, `courier'. WEIGHT This is normally `bold', `medium' or `light'. Other words may appear here in some font names. SLANT This is `r' (roman), `i' (italic), `o' (oblique), `ri' (reverse italic), or `ot' (other). WIDTHTYPE This is normally `condensed', `extended', `semicondensed' or `normal'. Other words may appear here in some font names. STYLE This is an optional additional style name. Usually it is empty--most long font names have two hyphens in a row at this point. PIXELS This is the font height, in pixels. HEIGHT This is the font height on the screen, measured in printer's points (approximately 1/72 of an inch), times ten. For a given vertical resolution, HEIGHT and PIXELS are proportional; therefore, it is common to specify just one of them and use `*' for the other. HORIZ This is the horizontal resolution, in pixels per inch, of the screen for which the font is intended. VERT This is the vertical resolution, in dots per inch, of the screen for which the font is intended. Normally the resolution of the fonts on your system is the right value for your screen; therefore, you normally specify `*' for this and HORIZ. SPACING This is `m' (monospace), `p' (proportional) or `c' (character cell). Emacs can use `m' and `c' fonts. WIDTH This is the average character width, in pixels, times ten. CHARSET This is the character set that the font depicts. Normally you should use `iso8859-1'. Use only fixed width fonts--that is, fonts in which all characters have the same width; Emacs cannot yet handle display properly for variable width fonts. Any font with `m' or `c' in the SPACING field of the long name is a fixed width font. Here's how to use the `xlsfonts' program to list all the fixed width fonts available on your system: xlsfonts -fn '*x*' xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-m*' xlsfonts -fn '*-*-*-*-*-*-*-*-*-*-*-c*' To see what a particular font looks like, use the `xfd' command. For example: xfd -fn 6x13 displays the entire font `6x13'. While running Emacs, you can set the font of the current frame (*note Frame Parameters::.) or for a specific kind of text (*note Faces::.). File: emacs, Node: Colors X, Next: Window Size X, Prev: Font X, Up: Command Arguments Window Color Options ==================== On a color display, you can specify which color to use for various parts of the Emacs display. To find out what colors are available on your system, look at the `/usr/lib/X11/rgb.txt' file. If you do not specify colors, the default for the background is white and the default for all other colors is black. On a monochrome display, the foreground is black, the background is white, and the border is gray if the display supports that. Here is a list of the options for specifying colors: `-fg COLOR' `--foreground-color=COLOR' Specify the foreground color. `-bg COLOR' `--background-color=COLOR' Specify the background color. `-bd COLOR' `--border-color=COLOR' Specify the color of the border of the X window. `-cr COLOR' `--cursor-color=COLOR' Specify the color of the Emacs cursor which indicates where point is. `-ms COLOR' `--mouse-color=COLOR' Specify the color for the mouse cursor when the mouse is in the Emacs window. `-r' `--reverse-video' Reverse video--swap the foreground and background colors. For example, to use a coral mouse cursor and a slate blue text cursor, enter: emacs -ms coral -cr 'slate blue' & You can reverse the foreground and background colors through the `-r' option or with the X resource `reverseVideo'. File: emacs, Node: Window Size X, Next: Borders X, Prev: Colors X, Up: Command Arguments Options for Window Geometry =========================== The `-geometry' option controls the size and position of the initial Emacs frame. Here is the format for specifying the window geometry: `-g WIDTHxHEIGHT{+-}XOFFSET{+-}YOFFSET' Specify window size WIDTH and HEIGHT (measured in character columns and lines), and positions XOFFSET and YOFFSET (measured in pixels). `--geometry=WIDTHxHEIGHT{+-}XOFFSET{+-}YOFFSET' This is another way of writing the same thing. `{+-}' means either a plus sign or a minus sign. A plus sign before XOFFSET means it is the distance from the left side of the screen; a minus sign means it counts from the right side. A plus sign before YOFFSET means it is the distance from the top of the screen, and a minus sign there indicates the distance from the bottom. The values XOFFSET and YOFFSET may themselves be positive or negative, but that doesn't change their meaning, only their direction. Emacs uses the same units as `xterm' does to interpret the geometry. The WIDTH and HEIGHT are measured in characters, so a large font creates a larger frame than a small font. The XOFFSET and YOFFSET are measured in pixels. Since the mode line and the echo area occupy the last 2 lines of the frame, the height of the initial text window is 2 less than the height specified in your geometry. In non-X-toolkit versions of Emacs, the menu bar also takes one line of the specified number. You do not have to specify all of the fields in the geometry specification. If you omit both XOFFSET and YOFFSET, the window manager decides where to put the Emacs frame, possibly by letting you place it with the mouse. For example, `164x55' specifies a window 164 columns wide, enough for two ordinary width windows side by side, and 55 lines tall. The default width for Emacs is 80 characters and the default height is 40 lines. You can omit either the width or the height or both. If you start the geometry with an integer, Emacs interprets it as the width. If you start with an `x' followed by an integer, Emacs interprets it as the height. Thus, `81' specifies just the width; `x45' specifies just the height. If you start with `+' or `-', that introduces an offset, which means both sizes are omitted. Thus, `-3' specifies the XOFFSET only. (If you give just one offset, it is always XOFFSET.) `+3-3' specifies both the XOFFSET and the YOFFSET, placing the frame near the bottom left of the screen. You can specify a default for any or all of the fields in `.Xdefaults' file, and then override selected fields with a `--geometry' option. File: emacs, Node: Borders X, Next: Icons X, Prev: Window Size X, Up: Command Arguments Internal and External Borders ============================= An Emacs frame has an internal border and an external border. The internal border is an extra strip of the background color around all four edges of the frame. Emacs itself adds the internal border. The external border is added by the window manager outside the internal border; it may contain various boxes you can click on to move or iconify the window. `-ib WIDTH' `--internal-border=WIDTH' Specify WIDTH as the width of the internal border. `-bw WIDTH' `--border-width=WIDTH' Specify WIDTH as the width of the main border. When you specify the size of the frame, that does not count the borders. The frame's position is measured from the outside edge of the external border. Use the `-ib N' option to specify an internal border N pixels wide. The default is 1. Use `-bw N' to specify the width of the external border (though the window manager may not pay attention to what you specify). The default width of the external border is 2. File: emacs, Node: Icons X, Next: Resources X, Prev: Borders X, Up: Command Arguments Icons ===== Most window managers allow the user to "iconify" a frame, removing it from sight, and leaving a small, distinctive "icon" window in its place. Clicking on the icon window makes the frame itself appear again. If you have many clients running at once, you can avoid cluttering up the screen by iconifying most of the clients. `-i' `--icon-type' Use a picture of a gnu as the Emacs icon. `-iconic' `--iconic' Start Emacs in iconified state. The `-i' or `--icon-type' option tells Emacs to use an icon window containing a picture of the GNU gnu. If omitted, Emacs lets the window manager choose what sort of icon to use--usually just a small rectangle containing the frame's title. The `-iconic' option tells Emacs to begin running as an icon, rather than opening a frame right away. In this situation, the icon window provides only indication that Emacs has started; the usual text frame doesn't appear until you deiconify it.