Working with Multiple Files

emacs enables you to edit several files in one session, each contained within its own buffer. To copy an external file into a new buffer, use the Ctrl+x Ctrl+f command. After entering this command, you see the following prompt on the echo line:

Find file: ~/

emacs is smart when it looks for files. It supports filename completion, which means that you can simply type a few characters of a filename, and emacs attempts to match a file (or files) to whatever you have typed so far. To do this, type .log and press the Tab key. emacs expands this to ~/.login, and you can see your .login file in a new buffer by pressing Return. If two or more files match the pattern supplied, pressing the Tab key cycles through them.

After you load a new file into emacs, you can switch between buffers by using the Ctrl+x b command followed by the name of the buffer that you want. The buffer’s name is that of the file that was loaded into it. The Ctrl+x b command also uses filename completion, so you can use the Tab key to cycle through your edit buffers after supplying a few relevant characters.

When you finish editing a buffer, instead of saving the contents by using the Ctrl+x Ctrl+s command, you might decide that you do not really want to keep the edits that you made. You can kill the current buffer by entering the command Ctrl+x k. emacs then prompts you for the name of the buffer to kill, but by simply pressing Return, you can kill the current buffer. Next, emacs asks for confirmation to which you can respond by typing yes (if you’re sure) and pressing Return.

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Tip:  
Whenever you are working with just two buffers, you can simply press Return after entering the Ctrl+x b command to switch to the other buffer.

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Copying and Moving Text

In order to copy and move blocks of text in emacs, you must define the region of text by marking the beginning and end points of the text block. This is done by moving the cursor to where you want the block to begin and marking it using the Ctrl+Space command (in this case, Space means literally pressing the spacebar). The end of the block is defined by wherever you place the cursor after that. To make a copy of the block, enter the command META+w. The text within the block is copied to emacs’s internal clipboard from which it can be pasted at another location using the Ctrl+y command. Alternatively, you can cut the block into the clipboard using Ctrl+w instead of META+w. Cutting, of course, deletes the text from its current location.

Let’s try out some of these techniques on your buffer asong2. Use the META+< command to jump to the beginning of the buffer. Enter a Ctrl+Space to mark the start of the block and then use Ctrl+n to move down a line. Cut the block to the clipboard using Ctrl+w, move the cursor to the end of the buffer using META+>, and paste it using Ctrl+y. The result is something like this:

It’s really quite swell

And all you have to do is spell

emacs works, if you let it!

This is a file for edit

And you have to give emacs some credit

Searching and Replacing Text

You can search forward and backward through text using the Ctrl+s and Ctrl+r commands, respectively. These commands, like many in emacs, use command completion. This is the same concept as filename completion: you supply a few characters, and emacs tries to fill in the rest. In this case, however, emacs moves the cursor to each instance it finds of the string supplied.

As you enter more characters, emacs narrows its search further. When you have found a correct match, press Return or use any of the cursor-movement commands to halt the search.

As with vi, searching in either direction wraps around the beginning or end of the file, depending on in which direction you are searching. However, when emacs reaches the top or bottom of the file, it tells you that the search failed. You can keep searching by pressing Ctrl+s or Ctrl+r accordingly, and emacs will continue using the current string.

To illustrate how searching in emacs works, let’s search backward through your file asong2. Enter Ctrl+r and type an s. emacs moves the cursor to the “s” in “works.” Next type a w. emacs now tries to find a pattern that matches the string sw. The cursor ends up on the “w” in “swell.” You can edit the search string by using the Backspace, or Delete, key. Delete the w and type a p. What happens?

Searches-and-replaces are done by entering the query-replace command. This is qualified by the META-x command, which tells emacs that the text to follow is a full command and not a key combination. After you enter the query-replace command, you are prompted for the string to be found. Enter the string and press Return. emacs then prompts you for the replacement string. After you enter the replacement string, emacs searches for every instance of the first string and, if it finds one, asks if it should be replaced with the second string.

Using Modes with Buffers

emacs is versatile enough to handle many different types of editing chores. It enables you to associate modes to buffers so that you can have text formatting specific to your editing application. If you enter the command Ctrl+x m, emacs enters mail mode that formats a buffer with To: and Subject: fields, as well as a space for the body of the mail message. emacs can even send the mail message for you (by entering Ctrl+c Ctrl+c) after you finish editing it.