Programs that allow you to view PDF and PS files are referred to
as text viewers. They do not allow a user to edit the text
directly, but do allow the user to view the pre-formatted text.
9.1. Working with
Text Editors
Red Hat Enterprise Linux comes with several applications that
can be used to write and edit program code. These programs are
text editors, programs that provide the
user with helpful highlighting and formatting options without
making changes or additions to the text. The most common of these
text editors are vi and Emacs. Two additional useful editors are
gedit and kate.
9.1.1. vi
vi is a shell prompt text editor.
This means that like less, opening an
instance of vi does not open a GUI
window. Instead, the contents of the file being edited appear in
the current terminal window. Because vi
works without a GUI, it can be used to edit text files even when
X is not working.
vi operates via keystrokes —
listed below is a small set of the keystrokes necessary to work
with text in vi.
| Key |
Action |
| [i] |
With a file open, press
[i] to enter Insert mode. This mode
allows you to move the cursor and to delete and add text anywhere
in the file. |
| [Esc] |
Pressing the [Esc] key at any time takes you out of Insert mode
and into Normal mode. |
| [w] |
[w] writes your changes to the file. Enter Normal
mode, press [Shift] -[:] , [w] , and finally
press [Enter] . |
| [q] |
[q] quits vi. Enter
Normal mode, press [Shift]
-[:] , [q]
, and finally press [Enter] . To save
your changes before exiting, enter :wq. To quit without saving your changes,
enter :q!. |
| [!] |
[!] forces vi to execute
the commands that precede it. |
Table 9-1. Useful keys in vi
vi uses many more keystrokes. To
learn more about vi, view the manual
page by entering man vi at a shell prompt.
You can also access the vim tutorial but
entering vimtutor command at a shell
prompt.
9.1.2. Emacs
Emacs is a text editor that includes
a GUI component. Like vi, Emacs also makes use of keyboard shortcuts to
manipulate text. Users can choose between working with the mouse or
the keyboard; all commands are available via either method.
Emacs can be customized extensively.
Programs that customize syntax highlighting or add other
functionality can be written and installed. Emacs even contains several games available from
the => menu, and a "psychiatrist" availabel from
the menu.
An Emacs tutorial is available by
selecting => from the main toolbar.
9.1.3. gedit
gedit is the GNOME text editor. It has highlight modes for
HTML, Perl, C, PHP, and many other languages. gedit features print preview, the ability to undo
your changes, and tabbed editing. gedit
is fully integrated with Nautilus.
9.1.4. kate
kate is the KDE text editor. It also has highlight modes for
multiple programming languages. kate
uses split screens to display multiple files. kate also has the ability to open a terminal
window within the application. kate is
fully integrated wtih Konqueror.
