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Next: 7. Shell Scripting Up: rute Previous: 5. Regular Expressions Contents
Subsections
6. Editing Text Files
To edit a text file means to interactively modify its content. The creation and modification of an ordinary text file is known as text editing. A word processor is a kind of editor, but more basic than that is the UNIX or DOS text editor.
6.1
vi
The important editor to learn how to use is
vi. After that you
can read why, and a little more about other, more user-friendly
editors.
Type simply,
|
vi <filename> |
to edit any file, or the compatible, but more advanced
|
vim <filename> |
To exit
vi, press 
, then the key
sequence
:q! and then press 
.
vi has a short tutorial which should get you going in
20 minutes. If you get bored in the middle, you can skip it and learn
vi as you need to edit things. To read the tutorial, enter:
|
vimtutor |
which edits the file
/usr/doc/vim-common-5.7/tutor,
/usr/share/vim/vim56/tutor/tutor, or
/usr/share/doc/vim-common-5.7/tutor/tutor,
5 10 |
================================================================================ W e l c o m e t o t h e V I M T u t o r - Version 1.4 ================================================================================ Vim is a very powerful editor that has many commands, too many to explain in a tutor such as this. This tutor is designed to describe enough of the commands that you will be able to easily use Vim as an all-purpose editor. The approximate time required to complete the tutor is 25-30 minutes, |
You are supposed to edit the
tutor file itself as practice,
following through 6 lessons. Copy it first to your home
directory.
Table 6.1 is a quick reference for
vi.
It contains only a few of the many hundreds of available commands
but is enough to do all basic editing operations.
Take note of the following:
vihas several modes of operation. If you press
, you enter insert-mode. You then enter
text as you would in a normal DOS text editor, but you
cannot arbitrarily move the cursor and delete characters while
in insert mode. Pressing will get
you out of insert mode, where you are not able to insert
characters, but can now do things like arbitrary deletions and
moves.
- Pressing
-
(i.e., : ) gets you into
command-line mode, where you can do operations like
importing files, saving of the current file, searches, and text processing.
Typically, you type : then some text, and then hit .
- The word register is used below. A register is a hidden clipboard.
- A useful tip is to enter
:set rulerbefore doing anything. This shows, in the bottom right corner of the screen, what line and column you are on.
6.2 Syntax Highlighting
Something all UNIX users are used to (and have come to
expect) is syntax highlighting. This basically means that
a
bash (explained later) script will look like:
instead of
Syntax highlighting is meant to preempt programming errors by
colorizing correct keywords. You can set syntax highlighting in
vim by using
:syntax on (but not in
vi). Enable
syntax highlighting whenever possible--all good text editors
support it.
6.3 Editors
Although UNIX has had full graphics capability for a long time now, most administration of low-level services still takes place inside text configuration files. Word processing is also best accomplished with typesetting systems that require creation of ordinary text files. [This is in spite of all the hype regarding the WYSIWYG (what you see is what you get) word processor. This document itself was typeset with LATEX and the Cooledit text editor.]
Historically, the standard text editor used to be
ed.
ed allows the user to see only one line of text of a file at
a time (primitive by today's standards). Today,
ed is
mostly used in its streaming version,
sed.
ed has
long since been superseded by
vi.
The editor is the place you will probably spend most of your time. Whether you are doing word processing, creating web pages, programming, or administrating. It is your primary interactive application.
6.3.1 Cooledit
(Read this if you ``just-want-to-open-a-file-and-start-typing-like-under-Windows.'')
cooledit
The best editor for day-to-day work is Cooledit, [As
Cooledit's author, I am probably biased in this view.] available
from the Cooledit web page <http://cooledit.sourceforge.net/>.
Cooledit is a graphical (runs under X) editor. It is also a
full-featured Integrated Development Environment (IDE) for
whatever you may be doing. Those considering buying an IDE
for development need look no further than installing Cooledit for
free.
People coming from a Windows background will find Cooledit the
easiest and most powerful editor to use. It requires no tutelage;
just enter
cooledit under X and start typing. Its
counterpart in text mode is
mcedit, which comes with the
GNU Midnight Commander package
mc. The text-mode
version is inferior to other text mode editors like
emacs
and
jed but is adequate if you don't spend a lot of time in
text mode.
Cooledit has pull-down menus and intuitive keys. It is not necessary to read any documentation before using Cooledit.
6.3.2
vi and
vim
Today
vi is considered the standard. It is the only editor
that will be installed by default on any UNIX
system.
vim is a
``Charityware'' version that (as usual)
improves upon the original
vi with a host of features. It
is important to learn the basics of
vi even if your day-to-day
editor is not going to be
vi. The reason is that every
administrator is bound to one day have to edit a text file over
some really slow network link and
vi is the best for this.
On the other hand, new users will probably find
vi
unintuitive and tedious and will spend a lot of time learning and
remembering how to do all the things they need to. I myself
cringe at the thought of
vi pundits recommending it to
new UNIX users.
In defense of
vi, it should be said that many people use it
exclusively, and it is probably the only editor that really can do
absolutely everything. It is also one of the few editors
that has working versions and consistent behavior across all
UNIX and non-UNIX systems.
vim
works on AmigaOS,
AtariMiNT, BeOS, DOS,
MacOS, OS/2, RiscOS, VMS, and
Windows (95/98/NT4/NT5/2000) as well as all UNIX variants.
6.3.3 Emacs
Emacs stands for Editor MACroS. It is the monster of all editors
and can do almost everything one could imagine that a single software
package might. It has become a de facto standard
alongside
vi.
Emacs is more than just a text editor. It is a complete system of using a computer for development, communications, file management, and things you wouldn't even imagine there are programs for. There is even an X Window System version available which can browse the web.
6.3.4 Other editors
Other editors to watch out for are
joe,
jed,
nedit,
pico,
nano, and many others that try to emulate the
look and feel of well-known DOS, Windows, or Apple Mac
development environments, or to bring better interfaces by using
Gtk/Gnome or Qt/KDE.
The list gets longer each time I look. In
short, don't think that the text editors that your vendor has
chosen to put on your CD are the best or only free ones out
there. The same goes for other applications.
Next: 7. Shell Scripting Up: rute Previous: 5. Regular Expressions Contents