CS 497C - Introduction to UNIX
Lecture 18: - The GNU emacs Editor
Chin-Chih Chang chang@cs.twsu.edu

Deleting, Moving and Copying Text
* To delete a character, use [Ctrl-d]. To delete a word, use [Alt-d].
* To delete text from the current cursor position to the end of line, 
  use [Ctrl-k].
* To delete the entire line, first use [Ctrl-a] and then [Ctrl-k][Ctrl-k].
* To delete text in a region, first mark the region and then use [Ctrl-w].

Deleting, Moving and Copying Text
* [Ctrl-y] is universally used to restore text from the deletion.
* While [Ctrl-w] deletes text in a region, the command to copy text is 
  [Alt-w].
* You can transpose two adjacent characters by using [Ctrl-t].

Changing Case of Text
* To convert an entire word to uppercase, move to the beginning of the 
  word and then press [Alt-u].
* You use [Alt-u] for converting a word to lowercase.
* To capitalize a single character, position the cursor under it and 
  then use [Alt-c].

Changing Case of Text and Command Completion
* For transforming case in large blocks of text, use a region. The 
  commands to convert text in a region are: [Ctrl-x][Ctrl-u] and 
  [Ctrl-x][Ctrl-l].
* The command completion feature can reduce some of the typing work.
* The guiding principle here is this: Enter as much of the command text 
  as you want and then press the [Tab] key.

Undoing and Redoing Editing
* To undo the change, there are three ways: [Ctrl-x]u, [Ctrl-_], [Ctrl--].
* If you continue to press [Ctrl--], you’ll undo the changes made before 
  the last save.
* If you keep pressing [Ctrl--], emacs starts redoing everything that 
  you have undone.

String Search
* The incremental and non-incremental search techniques are used in 
  string search in emacs.
* Incremental search is invoked with [Ctrl-s] followed by the search 
  string.
* After entering [Ctrl-s] emacs prompts for the search string in the 
  minibuffer. Suppose you're looking for mail. After m is entered, the 
  search starts immediately.

String Search
* The cursor relocates itself at the first instance of m - maybe on the 
  word moon.
* After mail is entered, press [Enter].
* There are a number of advantages of using incremental search:
 - The search is faster.
 - emacs tells you instantly whether the string exists in the file.
 - If there is a typo, backspacing erases the error.

String Search
* At the end of a file, use [Ctrl-r] instead of [Ctrl-s].
* To repeat  a search, you'll have to use the same command - [Ctrl-s] or 
  [Ctrl-r].
* In non-incremental search just press [Enter] and then type the string.
* Like vi, emacs uses a pattern comprising some special characters to 
  look for similar strings. This pattern is called a regular expression.