Summary


A good screen editor would have the simplicity and features of the basic UNIX system line editor, ed. It would support its use of regular expression and its sophisticated search and substitute capabilities-but with a screenful of text that provides context and allows the writer to think in terms of the content of paragraphs and sentences instead of lines and words. All of the editors covered in this chapter have been designed to address these requirements for a better editor.

vi, emacs, and vim are flexible, high-powered editors; they provide for sophisticated entering, modifying, and deleting of text. They have sophisticated search and replace capabilities, and they enable you to customize the editor’s operation by creating new commands.

vi is a superset of ed, and it contains all of ed’s features and syntax. In addition, vi provides extensions of its own that provide for customizing the editor. Users who are familiar with ed will find it easy to use vi because there are many basic similarities. vi, like ed, is an editor with two modes. When the editor is in command mode, characters you type are commands that navigate around the screen or change the contents of the buffer. When you are in input mode, everything you type is entered into the text.

emacs is a screen editor that is popular among UNIX System users. Although not always available as part of a particular variant of UNIX, it is a widely available add-on package. emacs is a single-mode editor-that is, it does not have separate input and command modes. Normal alphanumeric characters are taken as text, and control and metacharacters (those preceded by an ESC) are taken as commands to the editor.

vim is a superset of vi, and it contains all of vi’s features and syntax. In addition, vim provides extensions of its own to provide a more robust editing environment. This environment includes color syntax highlighting of text, the ability to develop and compile programming code and track it, and the ability to perform multiple “undo”s, as well as other scripting tools such as spell checking.

pico is a simpler model of a visual text editor that uses control-key functions to create and modify content. It is useful as a stand-alone editor, but is more useful to PINE e-mail users as a method of composing messages. The standard method of access to pico is to connect to a centralized-host system that supports both it and PINE, using server-side versions of the software. This is one reason that it is very popular with academicians that have access to university computers linked to other universities.

If you are not already a vi, emacs, vim, or pico user, you can decide which one you prefer by comparing the features of each one to see which ones you are most likely to use.




UNIX. The Complete Reference
UNIX: The Complete Reference, Second Edition (Complete Reference Series)
ISBN: 0072263369
EAN: 2147483647
Year: 2006
Pages: 316

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