3.3. Conventional Text Editors.
Section quotes:
- "I'd crawl over an acre of 'Visual This++' and 'Integrated Development
That' to get to gcc, Emacs, and gdb. Thank you."
-- By Vance Petree, Virginia Power
- "[VI] It is very powerful, which means it can be hard to do simple things,
BUT it also means that complicated thing are equally hard to do."
-- Romain Lerallut, The VI nano-HOWTO for the NewbieDoc Project.
Section contents:
3.3.1. Introduction.
Conventional text editors are part of Unix customs,
the first part of GNU project was EMACS - a text editor,
those text editor are very powerful, they are far from having an overloaded look,
but it's lovely and common between experts, they like them more than
nice looking GUI text editors.
Most configuration files are text files, and even those text editors
could be used by developers to replace IDEs. We will talk
about text editors that can work even without X graphical interface,
we have GUI text editors like 'gedit', 'kate' and more,
that are full of features like spell checking, syntax coloring
(useful for programming) and many more, but we won't talk about them,
the idea behind this section is that X is not always available
for example when X server has bad configuration and you are editing it,
or when you don't want to bother the server with drawing icons.
To be a good Unix user you have to know them (it's something you put in your CV),
We will talk about Vi, ViM, Emacs and Nano full-screen editors, don't ask LUG members what
do they prefer, there is a flame war between ViM and Emacs, and we will talk
about 'ed' line-oriented text editor.
 Tip
'mcedit' is a very simple console text editor comes with 'mc' package,
make sure you install it (while you are not expert on otther console text editors),
to open it's main menu press F9.
Tip
If you are familiar with 'WordStar' or 'Borland (Turbo) C for DOS',
then you may like 'joe' which has the same key binding.
3.3.2. VI text editor.
The first full-screen text editor in history! it's usually
installed not just as part GNU/Linux but also with many
rescue disks or minized base systems. With master distributions
'vi' is just a link to the new improved VIM, but it could
be provided by other (less featured packages) like 'nvi' or 'elvis'.
At first look, you will not be impressed, it has a voodoo like
behavior , the key to understand all that is to know that it works modes,
the first default mode (called normal mode) takes commands and operations,
and the other is for text entry (called insert mode) to activate it press 'i',
to go back to normal/command mode press 'ESC', at your terminal command line(bash)
type 'vi myfile', before your start typing press 'i',
now you can do normal editing, to exit press 'ESC' (to start normal mode) then
type ':q', if the file is modified you have to save it before exit
with typing ':wq', or to force edit without saving
type ':q!' with any of those don't forget to press '[ENTER]'
(we said type not press), to search press '/' (in normal mode) then enter
the text you searching for, to save the file type ':w'
at normal mode, to save it as another file, type ':w FILENAME',
you could open/edit another file ':e FILENAME',
yes 'vi' is multiple document editor, to move between files type
':prev' or ':next', also you could split the screen
with typing ':split', to move between the splited windows
use 'CTRL+w j' and 'CTRL+w k'.
VIM is similar, don't miss it.
3.3.3. VIM text editor.
|
Vi Improved (VIM), is very powerful text editor with millions of features,
type 'vim' at command line, run graphical versions like 'gvim' or 'kvim'
(option could be used for some features like '-A' for Arabic support if compiled),
use VIM the same way as vi, if you are not yet familiar with VIM you
could use 'evim' which is a link to vim that case it to run easy featureless mode.
|
|
Tip
To learn VIM first could run 'kvim' or 'gvim' twice then
press on one F1 for help and double click some section using the mouse
or use arrows and CTRL+']', read them and text them on the other VIM.
As in Vi it start in normal mode (operations and commands),
in which you could move with arrows to specify the position
where you apply some operation. We did not learn any so let's move
insert mode, press 'i' and use it as any text editor, move with arrows and type.
One of VIM best features is auto-completion for example type 'internationalization'
some where move other where and you want to type it, just type part of like 'inter'
then press 'CTRL+X' to enter completion mode then press
'CTRL+P' or 'CTRL+N' to complete it (if there
s many words start with 'inter' press it many times),
if you are typing a file name , just type part of it then press
'CTRL+X' then 'CTRL+F' and if there are many files use
'CTRL+P' and 'CTRL+N' to move between them,
another completion mode is dictionary use with CTRL+X followed by
CTRL+K, and you could make the dictionary yourself
as any file where each word on a line by itself.
Writing C++ files with VIM is now more easy, for example at 'gvim'
select 'syntax->CD->C++', while you are typing
C++ codes VIM indent blocks to have very readable file,
if you are editing an HTML file, select 'syntax->HIJK->HTML'
(submenus of syntax menu are alphabet letters initials of syntax name)
|
|
Let's have a real world experiment, open VIM and press 'i' then type:
Hello, world! I'm using VIM.
It's cool.
Look this is the 1st statement. And this is the 2nd one. And
there is more.
This is the second paragraph.
| k | one line upward |
j | one line downward |
l | next character |
h | previous character |
|---|
I know, you say to yourself that you will never usethem, well we'll see,
let's now take more useful commands:
| 0 | goto line begining |
^ | goto first non blank char on the line. |
$ | goto end of the line |
|---|
| |
| w | next word (at the first character) |
e | next word end(last character of the word) |
b | prevois word |
|---|
| |
| ( | next statement |
) | prevois statement |
{ | next paragraph |
} | previos paragraph |
|---|
altogether we have the following diagram:
k (up line) w/b word forward/backward
/\ e end of word
(prev letter)h <- -> l(next letter) 0/^/$ 1st/1st-nonblank/end of line
\/ '(' ')' prev/next statement
j (down line) '{' '}' prev/next paragraph
And this is the 2nd one. And
foobar And this is the 2nd one. And
To move the cursor to first occurence of some letter (only one character)
use 'f' or 'F' (forward or backword repectively) followed by the letter,
to repeate last search press ';', for real advanced searching,VIM offers
support for Regular Expressions (RE for short), it's a very powerful
method to represent what you are searching for, some characters has a special
meaning, for example '|' which mean 'or', see
'4.2. Back to command line.' section.
If you are searching for an email address that the user is the same as the
service provider (like ahmad@ahmad.com)
then the corresponding RE is '\([A-Za-z0-9]\+\)@\1.com',
to search for this RE forward type it after '/',
or backwork with '?', and to repeate last search press 'n'.
To search and replace a RE match with a text, use ':substitute'
or for short ':s', also you could specify lines to
search for example from 2 to 15 using ':2,15s',
to replace over all the text use '%' as range to be ':%s',
any way follow them with RE then replacement then options all separated by '/',
for example ':%s/Ali/Ahmad/gc', those options 'g' (global)
to replace all matches (many in the same line), option 'c' is used
to confirm replacement, you could use all RE features for example
to match whole word only use '<>'
for example ':%s/\<Ali\>/Ahmad/gc',
or this example (from VIM manual page) that will swap two statement
separated with a comma (to replace 'foo bar' with 'bar foo')
type ':%s/\([^,]*\), \(.*\)/\2 \1/'.
There are another VIM mode called 'visual mode', in this mode you type
moving operations then VIM will shade a region, then you press action
operations (unlike normal mode where you press action then movement).
To enter this mode, there are three methods, first press 'v',
look at this line:
This is a very long long line with meaningless english text.
|----------------------->
Ali Ahmad Belal
exam1 10 8 6
exam2 8 8 7
exam3 9.5 7 6
#include <gl.h>
#include <glu.h>
#include <glut.h>
#include <glui.h>
3.3.4. Emacs text editor.
There are many jokes found on it's package tells you where EMACS
name came from. This program is now a 'lisp' interpreter (an AI language),
on which Emacs were written at it's first stages, it's core now rewritten
on C and can have modules loaded at run time written on 'lisp'.
Emacs has many features like syntax coloring and indention for many
programming languages, games, completion, browsing the web, reading emails and
even helping the blinds (this is not an exaggeration). Unlike VIM, Emacs
works in single mode (or to be more specific Emacs modes does not mean
you can't type text as usual), to do some task you press a sequence of
keys that usually starts with 'CTRL' which is written in
documentation as 'C' for example 'C-x'
mean you hold CTRL and press 'x', another common key is Meta written 'M',
for example 'M-x' means 'META+x',
you ask where on earth this Meta key come from! it's a key
was common on computers that Emacs was designed on (long long ago, it was first GNU part),
in recent keyboards it could be 'ALT', for example 'M-x' means
'ALT-x'.
To find your first steps on Emacs see the tutorial with 'C-h t',
to read it's GNU information pages press 'C-h i', to see FAQs
press 'C-h F'. Each Emacs operation or action has a long name
(there exist actions that has no hot keys)m for example 'C-h i'
full name is info, to run an action using name press 'M-x' followed
by action name, for example 'M-x info' look at the buttom line
while you are typing commands, command names could be complicated and long like
'help-with-tutorial', that's why Emacs offer completion,
you could press '[TAB]', like GNU BASH which actually
borrow this feature from Emacs.
Emacs offers modes that in each it offer more features related to the mode,
for example 'cc-mode' for C,C++ and Java,
you will find a 'compile' on menus, and other related tools,
another mode is 'text-mode' which will be activated once
you entered a '.txt' to make a human readable file.
There are many tools (modes) like calender, choose it from tools menu
then you also get a new goto menu which could be used to move through it
even using other calenders, to know the first of Ramadan select Islamic
calender from goto menu, then enter the year,month name (eg. 'ramadan')
then the day (eg. 1), in this mode you could also display moon phases from
moon menu select Lunar phases, othter modes offers some games like AI asychiatrist (doctor) that
you could "talk" to (using your keyboard), type any thing then press ENTER
twice, see 'tools' menu.
To open a file press 'C-x C-f', to wait for a dialog box, look
down there, you see a place to type it's name (you could use TAB),
to save 'C-x C-s', to save as 'C-x C-w',
and to exit 'C-x C-c'.
3.3.5. Nano text editor.
A very simple small yet easy to use text editor that
depends on very few libraries, it look and feel as 'pico' with
more features. Debian selected it as it's default editor while installing.
Type 'nano' optionally followed by a file name to open,
you will see a screen with sections, big section on top (editing area),small
one on buttom (help and status), this help syntax like
'^G' which mean 'CTRL+G',
to get help press 'CTRL+G', to open (read) a file 'CTRL+R',
to save (write out) it 'CTRL+O', to justify text
'CTRL+J', to search (where is) 'CTRL+W', to check spelling
'CTRL+T' and to exit 'CTRL+X'.
3.3.6. Ed text editor.
Ed line-oriented text editor unlike full-screen text editors
it has ugly prompt where you could enter commands to select a line
then edit it by typing it's contenet again! this needs less memory
to hold the program and the text buffer being edited, this what old computers
at that time could do, there are many jokes about GNU Ed and GNU EMACS
found at GNU humor, one tells you why 'ed' is better than VIM and Emacs.
Type 'ed' and you will get... well, nothing!! this is a prompt to type commands,
you could pass an argument to 'ed' the file you want to edit, for example
'ed readme.txt'. Like Vi we have two modes the defualt command
mode and input mode, at the prompt type a command for example 'a' to add
text, then press ENTER (you should press ENTER after each command),
then you enter input mode and type what ever you like (more than one line
if you wish), then when you finish type period '.' on a line by itself
to stop input and go back to command mode, 'p' command will print
part of the buffer by default the current line:
bash$ ed myfile.txt
I'm using Ed the best text editor,
not only because it comes alphabetically first
before Vi and EMACS.
.
p
before Vi and EMACS.
| . | The current line. |
| $ | The Last line. |
| - | The previous line. |
| + | The next line. |
| N | The N-th line, 0 is before the first line. |
| -N | The line N steps upward. |
| +N | The line N steps downward. |
| N,M | From line N to line M |
| , | as '1,$' - all from first line to last line. |
| ; | as '.,$' - all from the current line to last line. |
| any lower case letter | Line marked with that letter using 'k' command. |
so to display all lines press ',p', to save use write command
by typing 'w' followed by the filename (if you like), to quit type 'q'
(another 'q' if the buffer is modified). Basic command found on the next table:
| Na | start input to add just after N, by default it's '.' |
| Rd | remove the region R, by defalt '.,.' |
| Rc | remove region R ('.,.' by default) then start input to add and replace it. |
| Rp | print region R by default '.,.' |
| N | let line N be the current. |
| RmN | move region R just after N |
| Rs/RE/STR/g | search for RE and replace it with STR |
| Rg/RE/COMMANDS | search for RE and apply COMMANDS on matches |
| NkI | mark line N with name I that is [a-z]. |
| ! COMMAND | run COMMAND using shell and display it's output. |
| e !COMMAND | drop current buffer and run shell COMMAND and edit it's output. |
| e FILE | drop current buffer and open FILE. |
| w FILE | save the buffer as FILE. |
| q | quit |
where N is a line specifier (need not be a number, it could be '-'),
and R is a range specifier in the form N,M or just N.
Let's continue on our prevois session
,p
I'm using Ed the best text editor,
not only because it comes alphabetically first
before Vi and EMACS.
p
before Vi and EMACS.
1a
ignore next lines
.
,p
I'm using Ed the best text editor,
ignore next lines
not only because it comes alphabetically first
before Vi and EMACS.
g/EMACS/d
s/first/first./
,p
I'm using Ed the best text editor,
ignore next lines
not only because it comes alphabetically first.
2m-2
2m+1
,p
ignore next lines
not only because it comes alphabetically first.
I'm using Ed the best text editor,
w delme.txt
q
|
Best viewed with free web browsers
You may get more high quality software
from here for free
Generously Hosted by www.JadMadi.net
|
