u02_vi_vim_tutorial.txt

vi / vim editor for a total beginner.

vi is a unix platform editor.
vi is a successor of QED, QED CTSS, ED, EX editors.
It was written by Bill Joy in 1976 as a multi-line
improvment of line editor "ex" that Joy had written with Chuck Haley.

You edit file by typing on unix prompt:

  vi  filename

Then you press "i" to enter "insert" mode - and start typing.
You press <ESC> to exit insert mode.
You press ":" to get command prompt at the bottom - and type "wq" and press <ENTER>
"w" = write
"q" = quit

=================================================
There are 3 modes:
 - insertion mode
 - command/navigation mode
 - ":"-commands mode

The editor begins in command mode, where you can: 
  navigate (move cursor), 
  delete, 
  copy(yank) / paste(put), 
  save/restore, 
  etc.

Insertion mode begins upon entering an insertion key (i,a,o,r, etc) 
or a change command (cw, etc.). 
Pressing <ESC> ends Insertion mode.

Most commands execute as soon as you type them 
except for "colon" commands which execute when you press the return key.
=================================================
File saving, reverting, quitting
:w          - write/save file
:w somefile - save to file "somefile"
:wq         - write & quit (same as :x   or  :ZZ )
:q  - quit (will quit if no changes made)
:q! - discard changes and quit
:e! - discard changes (revert to saved)

=================================================
Inserting text
i , I      insert before cursor, before line
a , A      append after cursor, after line
o , O      open new line after, line before
r , R      replace one char, many chars

=================================================
Motion
h , j , k , l    left, down, up, right (also arrows)
w , W            forward next word
e , E            forward end of word
b , B            backward beginning of word
( , )            sentence back, forward
{ , }            paragraph back, forward
0 , $            beginning, end of line
1G , G           beginning, end of file
nG or :n         line n
fc , Fc          forward, back to char c
H , M , L        top, middle, bottom of screen

=================================================
Deleting text:
dw      - deletes a word (type d followed by a motion)
dd      - delete line
:d      - delete line
x , X   - delete character to right, left
D       - deleteto end of line

=================================================
Yanking text (copying in a buffer) - type y followed by a motion:
y$ - yanks to the end of line.
yy         line
:y         line

=================================================
Changing text: "c" followed by a motion. 
It is effectively a deletion command that leaves the editor in insert mode.
cw - change a word
C          to end of line
cc         line

=================================================
Putting text:
p    put yanked text after position or after line
P    put before position or before line

=================================================
Bufers and markers: - Named buffers may be specified 
before any deletion, change, yank, or put command. 
Named markers may be set on any line of a file. 
Any lower case letter may be a name. 
I don't use them often - so removed them from this doc.

=================================================
Vim visual mode - used to copy/paste/delete:

v - mark first character of the block
<shift>-v - mark first line
<ctrl>-v - mark first column

then move the cursor to select the area, 
then press the "action":
  y - mark last character of the block and yank 
      block to this point 
  d - delete to this point

then move the cursor to some other place,
and use "p" or "P" to put the block there.

vawy - copy a word
vaby - copy a ( .. ) block
vaBy - copy a { .. } block

=================================================
Search for Strings:

/string    search forward
?string    search backward
n , N      repeat search in same, reverse direction
:se ic     set ignore case for searches
:se noic   back to case sensitive searches
Shift-5    jump between matching parenthesis (or curlies or brackets)

=================================================
Replace:

:s/pattern /string /flags  -  replace pattern with string
The search and replace function is accomplished with the :s command.
It is commonly used in combination with ranges or the :g command (below).

flags:
g , c     all on each line, confirm each
&         repeat last :s command

Example: 
find/replace in all the file (2 methods):

:%s/from/to/g
:g/from/s//to/g

=================================================
Regular Expressions:

. (dot)       any single character except newline
*             zero or more repeats
[...]         any character in set
[^ ...]       any character not in set
^ , $         beginning, end of line
\< , \>       beginning, end of word
\(: : :\)     grouping (putting into memory)
\n            contents of n th grouping (recalling from memory)

================================================= 
Counts:

Nearly every command may be preceded by a number 
that specifies how many times it is to be performed. 
For example, 5dw will delete 5 words 
and 3fe will move the cursor forward 
to the 3rd occurance of the letter e. 

Even insertions may be repeated conveniently 
with this method, say to insert the same line 100 times.

================================================= 
Ranges:

Ranges may precede most "colon" commands 
and cause them to be executed on a line or lines. 
For example :3,7d would delete lines 3-7. 

Ranges are commonly combined with the :s command 
to perform a replacement on several lines.
Example: replacement from current line to the end of the file:

     :.,$s/pattern/string/g 

Examples of ranges:

:n ,m        lines n-m
:.           current line
:$           Last line
:?c          Marker c
:%           All lines
:g/pattern/  All matching lines

================================================= 
Files operations:

:w file    - Write file (current file if no name given):
:r file    - Read file and insert its contents after current line
:n         - Next file
:p         - Previous file
:e file    - Edit file
:e!        - re-read current file (discard changes)
!!command  - run unix command "command"
:r!command - read in an output of shell command, for example:
:r!which perl

================================================= 
Other commands:

J     join lines
.     repeat last text-changing command
u     undo last change
U     undo all changes on line
ctrl-L    refresh the window

================================================= 
How to find/replace in all the file (2 methods):

:%s/from/to/g
:g/from/s//to/g
for example:
:g/<tab>/s//<space><space>/g

================================================= 
How to comment out current line and all following lines:

  . = current line
  $ = end of file
  .,$ = here to end
  %s = whole file

so try something like this:

  :%s/^/# / to comment
  :%s/^# // to uncomment

Here is how to do the same substituting the whole string
(just to demonstrate the use of memory variable \1)

:.,$s/\(.*\)/# \1/    to comment
:.,$s/^# \(.*\)/\1/   to uncomment

================================================= 
How to repeat insert 50 times:
50i-<ESC> - will repeat '-' 50 times

Note: you can repeat not only one character, 
but any text you type between 'i' and pressing <ESC>

To insert <ctrl-character> 
press <ctrl-v> <ctrl-character>

================================================= 
Today in Linux the "vi" is actually "vim" (vi improved). 

You can customize vim in file $HOME/.vimrc  

=================================================