LUG User Fest: Using the vi editor

Purpose

to cover the basics of using vi
to help new users feel comfortable with basic text editing, ie: conf file management

Why learn vi?

vi is everywhere.
You don't know when you'll HAVE to use vi.
Impress your friends! Pick up chicks (guys).
vi is fast, powerful, and uncluttered.

Other editors

Editor	ASCII or X Windows	Full-screen or line editor	Lexical parsing?
emacs	either	full-screen	yes
vi	ASCII only	full-screen	no (in ViM YES!)
pico	ASCII only	full-screen	no
ed	ASCII only	line editor	no
ex	ASCII only	line editor	no

Notes:

ASCII refers to text only.
X Windows refers to a graphical mode, reminiscent of MS Windows.
ASCII editors such as vi can still be used under X Windows by opening a psuedo-terminal such as xterm or aixterm; however they do not directly support the graphical features of X Windows.
Lexical parsing refers to the ability of some editors to recognize and highlight keywords in computer languages such as Fortran or C.

Eventually, you will fall in love with some bazaar variant of emacs and become religiously fanatic about it. That's fine- for now however, learning vi will help you get started and to eventually make an informed opinion about editors down the line.

vi is a very real part of the unix tradition, and its design clearly reflects that. vi was meant to be easy to use, not learn - that said, once you get used to vi you'll wish you could use it for all your text editing!

Overview of vi

vi modes

Two modes: Command mode, and input mode
Command mode is the default
In command mode, anything typed is interpreted as commands
To go to input mode, hit the letter i (or one of many other input commands)
Once in input mode, everything you type is interpreted as text
To return to command mode, hit the ESC key

vi commands

Case sensitive
Usually one or two characters
vi commands generally don't require hitting the ENTER or RETURN key
ex commands begin with colon (:) and require hitting the ENTER or RETURN key. ex is a line editor which underlies vi; vi is visual mode for ex.

Getting in and out of vi

To edit a file, enter the vi command from the UNIX command prompt:
Once in vi, you are automatically placed in command mode
To go to input mode, hit letter i
Begin typing text
Return to command mode by hitting the ESC key
To save the file, enter :w
To quit the file, enter :q
To save and quit, enter :wq
To quit without saving, enter :q!

Moving around

Moving one character at a time

Function	Key sequence
Move up one line	Letter k, or up arrow key
Move down one line	Letter j or down arrow key
Move left one character at a time	letter h or left arrow key
Move right one character at a time	letter l or left arrow key

NOTE: if you're in input mode, these movement keys are likely to show on your screen! His ESC to return to command mode before you move around!

Scrolling

Function	Key sequence
Scroll up one line	letter l or up arrow key
Scroll down one line	letter j or down arrow key
Scroll forward one screen	ctrl-f
Scroll backward one screen	ctrl-b
Scroll down half screen	ctrl-d
Scroll up half screen	ctrl-u

Global movements

Function	Key sequence
Go to a line, by line number	nG or :n (where n is a line number)
Go to the bottom of a file	G
Go to top of file	1G or :1
Display line numbers	:set nu
Suppress line numbers	:set nonu

Moving within a line

Function	Key sequence
Move right one character	letter l, or right arrow key
Move left one character	letter h, or left arrow key
Move to the beginning of a line	^ (carat)
Move to the end of a line	$ (dollar sign)

Moving by words

Function	Key sequence
Move to the next word (treating punctuation as separate words)	letter w (lower case)
Move to the next word (treating punctuation as part of the word)	letter W (upper case)
Move to the previous word (treating punctuation as separate words)	letter b (lower case)
Move to the previous word (treating punctuation as part of the word)	letter B (upper case)

Moving by paragraph

Move to the next paragraph	} (right curly bracket)
Move to the previous paragraph	{ (left curly bracket)

Locating text

Function	Key sequence
Find a string	Slash key (/) followed by string
Find next occurrence	Letter n
Search backward for a string	Question mark (?) followed by string
Search backward for previous string	Question mark (?) and enter key (or letter n)

Editing commands

Function	Key sequence
Insert	letter i
Append	letter a
Delete	letter d (upper-case D will delete to the end of a line)
Move	delete (letter d) followed by put (letter p)
Copy	yank (letter y) followed by put (letter p)

Adding text

Function	Key sequence
Go into input mode	letter i
Go into append mode	letter a
Add a line and go into input mode	letter o
Return to command mode	ESC key

Deleting text

Note: You must be in command mode to use the following commands.

Function	Key sequence
Delete a line	dd
Delete n lines	ndd (where n is the number of lines to delete, e.g. 2dd)
Delete a single character	letter x
Delete to the end of a line	letter D (upper case)
Delete a word	dw
Delete up to some string	d/string/

Copying text

Function	Key sequence
Get text into buffer (yank)	letter y
Put text from buffer onto screen (put)	letter p
Get a line into buffer	yy
Get n lines into buffer	nyy (where n is a number, e.g. 3yy)
Get all text from current cursor location, up to but not including some string	y/string
Get all text from cursor to bottom of file yG

Moving text

Moving text is done by first deleting it (d), then putting it (p). Please refer to the section above on deleting text.

Joining and splitting lines

Function	Key sequence
Join the next line to the current line	letter J (upper case)
Join the next n lines	nJ (where n is the number of lines)
Split a line	Hit letter i at location to split, then hit the enter key

More ways to add and replace text

Note: All the following commands (except r) leave you in input mode. Remember to hit the ESC key if you want to return to command mode.

Insert text at current cursor location	letter i
Insert text at beginning of line	letter I (upper case)
Append text after current cursor location	letter a
Append to end of current line	letter A (upper case)
Open new line below cursor	letter o
Open new line above cursor	letter O (upper case)
Substitute a single character at cursor	letter s
Substitute entire line at cursor	letter S (upper case)
Replace a single character (but don't go into input mode)	letter r
Replace current text	letter R (upper case)

Global replacements

Function	Key sequence
Substitute first occurrence of a string on the current line	:s/old/new/
Substitute all occurrence of a string on the current line	:s/old/new/g
Substitute all occurrence of a string within a range of lines	:nn,mms/old/new/g (where nn,mm is a range of line numbers separated by comma)
Substitute all occurrence of a string within a file	:1,$s/old/new/g (where 1,$ indicates the range of line numbers from line 1 to the end of file)
Same as previous (replace all occurrences in a file)	:%s/old/new/g (where % is an abbreviation for 1,$)
Global replacement, confirm substitutions	:%s/old/new/gc (You will be prompted as to whether to perform each substitution. Enter y to confirm, or just hit enter to bypass)

Repeating and undoing edits

Function	Key sequence
Repeat	period (.)
Undo last change	letter u
Undo all changes on current line	letter U (upper case)

Edits across files

Reading and saving into other files

Function	Key sequence
Read another file into current file at cursor location	:r filename
Read another file into current file, place it after some line number	:nnr filename (where nn is a line number; $ is end of file)
Write text from current file to a new file	:w newfile
Overwrite an existing file with the contents of the current file	:w! some.file
Use % (current filename) to create a new file	:w %.new
Append text from current file to another existent file	:w >> newfile
Write a range of lines from current file to another file	:nn,mmw newfile (where nn,mm is a range of lines; $ means end of file)

Editing multiple files

To edit another file while editing a file, use :e :e filename Then use :e # to switch to the alternate file: :e # You can also specify two filename on the vi command: vi file1 file2 Initially you are placed in an edit session for the first file. To edit the second file in the sequence, use: :n To go back to the alternate (first) file, use: :e #

Using named buffers

vi provides up to 26 named buffers (a-z)
You can store text from an edit command into a named buffer to be retrieved later. Precede an edit command with double quote and a buffer name.
Example: Yank a line into a named buffer, buffer b:
Once the buffer has data stored into it, it can be retrieved using the put (p) command. Example:
Copying is done by a sequence of yank and put; move is done by a sequence of delete and put.
Delete a line and store it into buffer b: You can then move your cursor, and use "bp to move the text to the new location.
Named buffers are stored across edit sessions. You can use the :e command to edit a second file while still inside the first. The use p to retrieve named buffers.
% and # refer to the current and alternate filenames. To switch from to the other file, enter:

Tailoring vi

Set commands

Function	Key sequence	Abbreviation	Turn off
Ignore case during a search	:set ignorecase	:set ic	:set noic
Display line numbers	:set number	:set nu	:set nonumber
Report changes larger than n lines (default is 5)	:set report=n	none	none
Show current mode (input, replace modes)	:set showmode	none	:set noshowmode
Searches will wrap around the end of file	:set wrapscan	:set ws	:set nows
Change the tabstop to something (X) which isn't annoying	:set tabstop=X	:set ts=X	:set ts=8

Note: In general, you can always turn off an option by preceding it with no.

Creating a vi profile

vi reads .exrc from your home directory as it's profile
set commands in the .exrc file should not include the colon

Summary of most useful commands

Function	Key sequence
Save current file	:w
Save and quit	:wq or, just :x
Quit without saving latest changes	:q!
Go into input mode	i
Return to command mode	ESC key
Add a line and go into input mode	o
Go into replace mode	R
Replace a single character	r
Delete a single character	x
Delete a line	dd
Delete n lines	ndd (e.g. 3dd, 5dd)
Delete to end of current line	D
Delete to end of file	dG
Go to top of file	:1
Go to botton of file	G
Scroll forward one screen	ctrl-f
Scroll backward one screen	ctrl-b
Copy a line	yy followed by p
Copy n lines	nyy followed by p
Copy up to but not including some string	y/string followed by p
Global change	:%s/oldstring/newstring/g
Show modes	:set showmode
Show line numbers	:set number (turn off with :set nonu)

Where can I get more information?

A quick search of the web can find a ton of information about using the vi editor- in particular, you should check out http://www.vim.org, the homepage of the ViM (vi Improved) editor. ViM includes many bug fixes and enhancements over the POSIX definition of vi, while maintaining almost 100% compatibility. Everyone should use VIM. :)

Most of the contents of this page were shamelessly ripped from the web.