Introducing XEmacs

If you're going to use a UNIX operating system like Linux, there simply is no avoiding emacs. You've probably heard of it, the powerful text editor that provokes wars between its devoted fans and fans of its more ancient but still omnipresent competitor vi. To those of us migrating to Linux from a more graphically oriented environment, both programs seem alien. You might think you can escape by using some other program, but you can't escape because every program you pick up tries to imitate emacs in some way.

Getting to know emacs may be a necessity, but it's no picnic for immigrants from other operating systems. We know that emacs is "powerful", and we would like to access all that power, but it's so hard just to get started editing a file! Most beginners will start up emacs thinking it will be like any word processor. Fifteen minutes later they are rebooting their computer, having been unable to figure out how to do anything (including exit the program).

Don't give up! XEmacs will solve your text editor woes, because it wraps up all the power of emacs inside a comfortable graphical user interface with buttons and menus to give you access to the most common operations. Now you can start editing immediately!

Formerly known as Lucid Emacs, XEmacs was developed by a "collaboration of Lucid, Inc. with Sun Microsystems, Inc. and the University of Illinois with additional support having been provided by Amdahl Corporation, INS Engineering Corporation, and a huge amount of volunteer effort." (Quoted directly from the XEmacs About box.) It was initially based on GNU Emacs 19 and has kept pace with newer versions.

There are two kinds of computer people, the keyboard people and the mouse people. Mouse people will be happy with XEmacs because they will actually be able to use it (unlike many Linux editors that never heard of a mouse). Keyboard people will fall in love with XEmacs (and emacs in general) because there are so many amazing things you can do with just a few keystrokes. But even mouse people will have to learn a few of the keyboard tricks in order to get by. What follows should be enough information to get you started editing files with XEmacs, and give you the know-how to find out the rest for yourself.

Obtaining and Installing XEmacs

For some unfathomable reason XEmacs is not included with every Linux distribution. Neither my Red Hat 5.1 nor S.u.S.E. 5.2 distributions contain it. If you're using a distribution that supports RPMs you can download the latest RPM package from Red Hat Contrib|Net. There are multiple versions posted there, so make sure to pick the right one for your distribution. Personally, I fetched version 20.4 for glibc2 (libc6) based distributions (Red Hat 5+).

If you don't have RPM support, or if you are using a system other than Linux (XEmacs runs on most UNIX systems and Win32), you'll want to grab the source code archive from the XEmacs home page. Don't be scared of that word "source". Compiling this program is very easy to do since it follows standard GNU procedures. You simply need to extract the archive to a temporary directory [tar xzvf *.tar.gz], run the configure script [./configure], build the program with gnu make [make] and install it [make install]. You may also want to grab some of the accessories in separate RPMs(or tar.gz's), but they are not needed to run XEmacs.

Like its brother GNU Emacs (and despite its name), XEmacs runs on the console as well as in X, so you can learn just one editor rather than one per environment. You don't get the full advantage of XEmacs, however, unless you run it where it runs best, under the X Window System. The first time you fire it up there, you'll feel like you've come home. There's a nice menu bar across the top with familiar looking entries like "File", "Edit" and "Help", and a row of command buttons under that for all your common operations: open, save, print, cut, copy, paste. From this point you can probably fiddle with the menus and get a file opened, changed and saved without any help. But in order to master XEmacs, there are a few "secrets" you'll need to know.

---

Understanding XEmacs Terminology

Ordinarily I would not bother going over simple terminology used in a program's documentation, but this is necessary with XEmacs because it uses a few terms that are not "normal", or not used in normal ways. Figure 1 will serve as a useful reference for most of this discussion, as it identifies the major elements of the XEmacs frame and mode line.

First, there is a shorthand used in XEmacs documentation (and most other Linux documentation) for describing key combinations. A capital "C" followed by a dash ("C-") means to hold the Control key down while pressing the following key. So "C-m" means to hold the Control key while pressing "m". A capital "M" followed by a dash ("M-") means to hold down the Meta key. PC's don't have a Meta key, so usually this means the Alt key. (It may be only the left Alt key or only the right, or both, depending on your distribution/configuration.) Thus "M-x" means "Alt-x".

You will find in the XEmacs documentation many references to buffers (and even a menu by that name). A buffer is roughly what we would call an open file, although some buffers contain information that is not a file. And according to the XEmacs documentation, you don't open a file, you visit one. (The file menu disagrees.) So a buffer contains a file that you are currently visiting.

The XEmacs Screen

The window that contains the XEmacs screen is referred to as the frame. That frame can be divided into windows that look like divisions of the "main window". (See Figure 1) Each window displays a buffer (but you can have buffers that are not displayed in a window). At the bottom of each window is a mode line, which we would think of as a status bar. A detailed explanation of the mode line will follow shortly. At the very bottom of the screen is one line called the echo area. The echo area is where you and XEmacs communicate with each other. Status messages and "hints" will appear there, or input will be requested via a minibuffer, as it is sometimes called in the documentation.

When you hover the mouse over an area of the mode line, the echo area gives a brief explanation of what the item under the cursor is or does. (See Figure 1) The mode line always begins with two dashes (--). At the left side of the mode line, next to the dashes, is a two character indicator of the status of the current buffer. Dashes (--) mean the buffer is "clean" or unmodified. Asterisks (**) mean the buffer is "dirty", or has been modified and contains unsaved changes. Percent signs (%%) indicate that the buffer is read-only. Next, the mode line displays the name of the current buffer, followed by a list of the currently active modes. Following this are some indicators of your position in the buffer. The item beginning with "L" is the line number where the cursor is (an optional indicator that I activated). The last entry on the mode line gives a clue about how much of the buffer is "behind" you. "All" means that the entire buffer is visible in the window. A percentage (30% here) indicates how much of the buffer lies above the top of the window.

You can right-click on areas of the mode line and get a context sensitive menu of possible actions. Right click on the buffer name and you will get a menu of active buffers you can display in the window. Right click on the mode area and get a menu of minor modes that can be activated. Right clicking elsewhere gives you a list of window manipulation commands.

Speaking of right clicks, you won't see that phrase in the XEmacs documentation. Unix workstations traditionally use a three-button mouse, and the documentation refers to mouse buttons 1, 2, and 3. Button 3 is a right click, button 1 is a standard left click, and button 2 is a click of the middle mouse button. If your mouse doesn't have a middle button, you might be able to simulate a middle click by clicking both buttons at the same time. (This behavior is controlled by your X server, not XEmacs.) Many XEmacs command depend on button 2, the middle button, and I highly recommend you get a three button mouse. You can pick one up anywhere they sell mice.

Below the mode line, on the last line of the frame, lies the echo area, also called the minibuffer when used for input. In addition to relaying messages to the user, the echo area acts like a tiny command line, where you can give XEmacs instructions on how to do its job. Whenever you use a key sequence that requires input to complete the command, XEmacs gets that input via the minibuffer in the echo area (so if it seems to be ignoring you, check the bottom of the screen to see if it's waiting for you to answer a question).

Occasionally you may find yourself stuck in the minibuffer. You probably typed a control key sequence that didn't do what you thought. Like a modal dialog, the minibuffer prevents you from editing while it is active. You must cancel it to continue working, but ESC does not do the trick! When this happens, the key you want is C-] (Control + right square bracket). Don't ask me why.

"Delete...No, I said DELETE!...ARRRGH!

The first and most annoying thing that PC users will discover about XEmacs is that the backspace key backspaces, and the delete key also backspaces! The reason for this peculiar behavior no doubt goes back to the ancient days of Unix, but it has never been satisfactorily explained to me. To fix it, click the Options menu, choose Customize->Emacs->Editing->Basics->Delete Key Deletes Forward. Once that's done, be sure to click Options->Save Options so it will stick! (The key that normally "deletes" in XEmacs is Control-d, which still works.) Bear in mind, however, that the XEmacs documentation is written with the default configuration in mind, so when it says to press <DEL>, it usually means the backspace key.

Using XEmacs

Although the command buttons at the top of the screen make it easy to access the basic editing functions, you'll want to know the keyboard commands to increase your speed. The chart below should serve as a good reference to get you started. Where multiple key combinations are listed, some may not work with all configurations, let trial and error verify yours. There are a few other things you should take note of.

To open or visit a document, you type C-x,C-f. Note that if you press the Open button or choose File->Open from the menus, you'll get a dialog box to help you find the file. If you use the keyboard shortcut, the dialog box does not appear, and you are prompted to enter the filename in the minibuffer. Command line completion works here as it does at the shell prompt, by pressing TAB. Pressing TAB twice opens a DirEd (Directory Edit) buffer, which works like a little file manager to help you locate the file you want. Don't double-click! Selecting items in the DirEd buffer is done with mouse button 2, the middle button.

You will also notice early on that there is no "New" button and no File->New option on the menu. To create a new, blank document, use the File->Open command (or any equivalent) and specify a file name that does not already exist. The file will be created for you when you save it. There is also no File->Close option on the menu. The keyboard equivalent is C-x k ('kill-buffer').

Once you are in a regular buffer, you will find that the standard editing keys you are accustomed to will behave as they do on Windows or Mac word processors (see the chart for details), with a few exceptions. The Undo command, for example, is normally bound to C-z on Windows, but that key is already taken in XEmacs. So instead we use C-_ (that's Control Underscore, which on PC keyboards is Control-Shift-Dash), or C-x u.

"Clipboard" Operations

As you would expect, XEmacs supports the standard cut, copy and paste operations. A common cause of confusion, however, is the fact that XEmacs has its own internal "clipboard" called the kill-ring, in addition to the standard X clipboard. Normally they work together and contain the same text, but because other programs have access to the X clipboard, they sometimes get out of sync. This results in different paste commands pasting different text. Pressing the middle mouse button pastes from the X clipboard. Pressing C-y pastes from the XEmacs kill-ring. This might be disturbing at first to former Windows users, but it is easy to get used to.

One cool feature that XEmacs has over Windows is the ability to accumulate text in the kill-ring or in a buffer. Normally the copy command replaces the clipboard and/or kill-ring contents with the current selection. The C-M-w (that's Ctrl-Alt-w) command causes the selected text to be added to the text in the kill-ring instead of replacing it. There are also commands that append the selected text to a special buffer, but these are not bound to keys by default. See the XEmacs documentation for details.

XEmacs Modes and Features

One of the things that makes XEmacs so powerful is its special editing modes. XEmacs recognizes many different kinds of files, and has specific menus, commands, and display settings for each kind of file that it recognizes. For example, if you open a file called foo.c, a menu appears containing commands particular to the C programming language. If you open and HTML file, several menus give you a host of options for editing HTML mark-up. (See Figure 1) XEmacs has modes for dozens if not hundreds of different languages and file types, including shell scripts, C, HTML, SGML, Python, Perl, LaTeX, Texinfo, nroff, the list goes on and on.

The modes that specify the language are called Major Modes, and only one can be active at a time for any one buffer. There are also Minor Modes that can specify behavior of XEmacs while in a particular buffer. Many minor modes can be active at the same time. For example, Syntax Highlighting (called Font Lock Mode) can be activated in any buffer where XEmacs knows about the language. See Figure 1 for an example. Auto Fill mode causes XEmacs to insert end-of-line characters as you type to wrap long lines. Ispell mode can be invoked to spell check each word as you type it. Abbrev mode implements a customizable replace-as-you-go dictionary, replacing "ILCN" with "Incredibly Lengthy Corporation Name", for example, to save a lot of wear on your fingers. In proprietary software, these features would be found only in expensive word processors.

Not only does XEmacs support many other features you would expect to find in advanced word processors, such as AutoSave and Version Control, but it has many that proprietary word processors only wish they had. Check out the Apps menu and you'll find a built-in calendar program that knows the cycles of the moon, an email and Usenet client, a complete World Wide Web browser, and of course, a collection of time-wasting games.

INFO Documentation

That should be enough to get you started with XEmacs. The only other thing you'll need to know is how to get help and learn more. XEmacs makes that easy, as it comes with a complete reference and a New User's Guide in texinfo format. Press the "info" button at the top of the screen, or select a topic from the Help menu to access the documentation in a separate XEmacs frame.

The XEmacs info frame works the same as the normal info browser (type info at the command line for details), with a few enhancements. Navigation buttons have been added to the button bar providing access to the Previous, Next, and Up relative nodes. There is still no button for the "Last Visited" node, so you'll need to use the "L" key to back up. Hyperlinks may be activated by clicking the middle mouse button (button 2), and text can be copied to the clipboard or kill-ring using standard commands.

The info documentation contains a complete XEmacs manual that tells you everything you need to know to operate and customize XEmacs. The New Users Guide is the best place to start. It will help you get familiar with standard XEmacs operations. The included XEmacs FAQ is vast and well-organized. It even cross-references related questions. If you have a thorny problem, and you can't find the answer in the manual, chances are it is in the FAQ. The latest version of all these documents is available via the web at the XEmacs home page.

Summary

XEmacs is an astoundingly capable and complex editor. Installation is as easy as a Linux program gets. The sharp learning curve of the console-based GNU Emacs has been blunted somewhat by clever graphical design, allowing new users to begin editing immediately, but new users will still take some time to get completely comfortable with XEmacs. The thorough documentation is an excellent resource to novice and expert alike, but is not searchable. Users looking for a general word processor could get by well with XEmacs, but will probably be happier with StarOffice or WordPerfect. However, to those who edit "special" text like programming languages or mark-up languages such as HTML, XEmacs' editing modes will quickly become an indispensable part of daily life. Most importantly, XEmacs has the same ancient lineage as Linux itself, and the skills learned here, from shortcut keys to customization files, can be applied to Linux administration and any number of other software tasks.

Resources

XEmacs home page

XEmacs Documentation on the Web

Info documentation accompanying the software (described above)

Chart of Common XEmacs Commands & Keys

Common XEmacs Keyboard Commands

Quitting XEmacs
C-x C-c	Exit XEmacs. If there are unsaved files open, XEmacs will ask you to save them.
C-z	Suspend XEmacs. If used under the X window system, this command will shrink the XEmacs frame to an icon.
File Operations
C-x C-f	Find File. Visit or Open a file.
C-x C-s	Save the current buffer.
C-x s	Save All. Offers to save all modified buffers.
C-x C-w	Save As (Write). Save the current buffer under a new name.
C-x k	Close file. Offers to save the current buffer if modified, then kills it.
Editing Operations
C-w	Cut selected text to the kill-ring.
M-w	Copy selected text to the kill-ring.
C-y	"Yank" or Paste the kill-ring contents at the cursor.
C-d	Delete the current selection (without placing in kill-ring)
C-x u C-_	Undo one batch of changes (usually, one command's worth).
Cursor Movement
C-a Home	Move the cursor to the beginning of the line
C-e End	Move the cursor to the end of the line
M-b C-LeftArrow	Move the cursor backward one word
M-f C-RightArrow	Move the cursor forward one word
M-< C-Home	Move the cursor to the beginning of the buffer
M-> C-End	Move the cursor to the end of the buffer