VI - EDITOR

INTODUCTION TO VIM

• vi → The standard Unix text editor

• vim → vi improved is a powerful text editor

• gvim → Graphical version of vim

• Advantages of Vi / Vim :– Speed : Do more with fewer keystrokes– Simplicity : No dependence on mouse/GUI– Availability : Included with most Unix / Linux Distro

• Disadvantages of Vi/Vim :– Difficult : Steeper learning curve than simpler editors

VI MODES OF WORKING

• Keystroke behavior is dependent upon vim's "mode"

• Three main modes:– Command Mode (default) : Move cursor, cut / copy / paste /

or delete text in file – Insert Mode : Modify text in file– Ex Mode : Save, Quit, Customize etc

• <Esc key > : exits current mode into command mode.

• NOTE : When in doubt press Escape key, you will be back in command mode

OPEN A FILE IN VI / VIM

• To start vi / vim :– # vim filename– # vi +number filename ( open file and put cursor at line number

specified )

• If the file exists, the file is opened and the contents are displayed

• If the file does not exist, vi creates it when the edits are saved for the first time

• By default vi has unnamed temporary buffer where file is edited

MODIFY A FILE : INSERT MODE• INSERT MODE → To insert the text in file we should be in Insert

mode– i → inserts the text before cursor location– I → insert at beginning of line– a → inserts text after cursor location– A → insert at end of line– I → insert at beginning of line– o → insert new line (below)– O → insert new line (above)– S → deletes the character under cursor and get into insert

mode

MODIFY A FILE : REPLACING TEXT

• ONE CHARACTER AT A TIME → Replacing text also happens in insert mode as follows :

– r → replace a single character– R → replace multiple char( will be in replace mode )

SAVE & EXIT FILE : EX MODE• Enter Ex Mode by pressing → :

– Creates a command prompt at bottom-left of screen

• Common write/quit commands :

– :q <enter key> → quits the vi only if no changes have been made to the file being edited

– :q! <enter key> → quits the vi without making any changes in file

– :w <enter key> → writes (saves) the file to disk only

– :wq <enter key> → writes the buffer and quits vi

– :ZZ <enter key> → writes the buffer and quits vi

– :x <enter key> → writes and quits

WRITE TO FILE : EX MODE• Common write commands :

– :w <enter key> → writes (saves) the file to disk only

– :wq <enter key> → writes the buffer and quits vi

– :f <filename> → renames current file to filename

– :w <filename> → write the file to path / filename given

– :w>> filename → append current file to the filename given

– :5,10w filename → write lines 5 through 10 to the filename given

– :5,10w>>filename→ append lines 5 through 10 to the filename given

– :r <filename> → read a copy of file into current file at cursor positon

– :e <filename> → opens another file with filename

– :e# <enter key> → switch between the open vi windows ******** (this works after saving the file once on disk using :w )

USING COMMAND MODE

• Default mode of vim

• Keys describe movement and text manipulation commands

• Commands repeat when preceded by a numberCommands repeat when preceded by a number

• Example– Right Arrow : moves right 1 character– 5 followed by Right Arrow : moves right 5 characters

MOVING AROUND : COMMAND MODE

• Move by character : Arrow Keys, h, j, k, l

( Non-arrow keys useful for remote connections to older systems )

MOVING AROUND : COMMAND MODE

• MOVE BY WORD

• w : moves the cursor forward one word

• b : moves cursor back one word

• e : moves cursor to the end of current word

• MOVE BY LINE

• ^ : moves cursor to the beginning of current line

• $ : moves to the end of current line

• MOVE BY SENTENCE

• ( : moves to the beginning of previous sentence

• ) : moves to the end of next sentence

MOVING AROUND : COMMAND MODE

• MOVE BY PARAGRAPH

• { : moves to the beginning of previous paragraph

• } : moves to the end of next paragraph

• MOVE BY SCREEN

• <ctrl>f : moves forward one screen

• <ctrl>b : moves back one screen

• <ctrl>d : moves down half screen

• <ctrl>u : moves up half screen

• H : first line on screen

• M : middle line on the screen

• L : last line on the screen

MOVING AROUND : COMMAND MODE

• MOVE INSIDE WHOLE DOCUMENT

• nG : move to nth line of file (****in command mode*****)

• :n : move to nth line of file (****in ex mode****)

• 1G : first line of the document / file

• G : last line of the file

• 25G : 25th line of the file ( in command mode )

• :25 : 25th line of the file ( in ex mode )

SEARCH : EX MODE

• Same implementation as in less editor

• /<pattern> – search forward in buffer for next occurrence of the pattern of text.

• ?<pattern> – search backwards

• n – Repeats the last search command

• N – Repeats the search command in opposite direction

• We can use regular expression in searches

SUBSTITUTION : EX MODE• By default substitute the first occurrence of text on current line

– : s/file/book/ ( first occurrence of file with book on current line )

– :s/file/book/g ( all the occurrence of file with book on current line )

• Use x,y ranges – :1,5s/cat/dog/ ( first occurrence of cat with dog between

line 1 to line 5 )– :1,5s/cat/dog/g ( all occurrence of cat with dog between line

1 to line 5 )

• Use % for whole file– :%s/cat/dog/ ( substitute first occurrence of cat with dog in

full file )– :%s/cat/dog/g ( substitute all occurrence of cat with dog in

full file )– :%s/cat/dog/gc ( c → prompt before each substitution )

DELETING TEXT : COMMAND MODE

• DELETING SINGLE CHARACTERS– x → Deletes a character at current cursor position– 3x → Deletes the character currently under cursor

followed bye two– Nx → Deletes n-1 characters on right of cursor position– X → Deletes a character to the left of the cursor

• NOTE : Deleting puts the text in unnamed temporary buffer which can be used for paste operation at other place, and thus becomes cut paste *******

DELETING TEXT : COMMAND MODE• DELETING LARGER CHUNKS

– dw → deletes a word (or part of a word) from the cursor to the next space or to the next punctuation.

– db → delete one word backwards

– d$ → deletes the current line from the cursor to the end of the line

– d^ → deletes the current line from the cursor to the beginning of the line

– d0 → same as d^

– d) → delete one sentence forward

– d( → delete one sentence backwards

– dG → delete from current line to the end of file

– dgg → delete from current line to the beginning of file

– dd → deletes the current line *******

– ndw → deletes n words from current cursor position

– ndd → deletes n lines from current line *******

COPY TEXT : COMMAND MODE• COPY / YANKING → yank command puts the text in temp buffer for copy

– yw → yank a word forward

– yb → one word backwards

– y$ → yank the current line from the cursor to the end of the line

– y^ → yank the current line from the cursor to the beginning of the line

– y0 → same as d^

– y) → yank one sentence forward

– y( → yank one sentence backwards

– yG → yank from current line to the end of file

– ygg → yank from current line to the beginning of file

– yy → yank the current line *******

– nyw → yank n words from current cursor position

– nyy → yank n lines from current line *******

– 20yy → yank 20 lines from current line *******

• P → 'PUT' comman for paste operation, place the contents of the unnamed buffer back into the file. ( Buffered content of delete & yank command )

– p → Paste the content below the current line– P → Paste the content above the current line

PASTE TEXT : COMMAND MODE

UNDO CHANGES : COMMAND MODE

• u → undo most recent change

• U → undo all changes to the current line since the cursor landed on the line

• Ctrl-r → redo last "undone" change

USING MULTIPLE “WINDOWS”

• View multiple documents in a single vim screen.– Ctrl-w followed by s → s splits the screen horizontally– Ctrl-w followed by v → v splits the screen vertically– Ctrl-w followed by arrow → Arrow moves between windows

– Ctrl-w followed by q → quit / close open windows

• Ex-mode instructions always affect the current window

• :help windows displays more window commands

CUSTOMIZING VI SESSION• A few common configuration items

– :set all - Display all options– :set - Display current setting of

options– :set number / :set nu - Display line numbers

– ( This can be useful when deleting or substituting selected text as follows )

– :2,10d - Delete line 2 to 10– :1,10s/foo/bar/g - Substitute foo with bar

from line 1 to 10

– :set nonumber / :set nonu - Hide line numbers

CUSTOMIZING VI SESSION• A few common configuration items

– :set all - Display all options– :set - Display current setting of

options– :set autoindent or :set ai - Turn on autoindenting– :set textwidth=65 (vim only)– :set wrapmargin=15 / :set wm=15 - Set wrap margin 15

spaces from right edge of screen

– :set wrapmargin=0 / :set wm=0 - Turn off Wrap margin– :set ignorecase or :set ic - Set ignore case during

searches– :syntax on - Turn on syntax

highlighting– :syntax off - Turn off syntax

hightlighting

CUSTOMIZING VI SESSION• Options can be set in the following ways

– During a vi session• :set nu / :set nonu ...etc ( preserve setting for that session)

– For permanent setting for a user.• Create either ~/.vimrc or ~/.exrc file in user home directory

Sample contents of .exrc are →

set nuset aiset wm=10

ABBREVIATIONS • ABBREVIATIONS → are text strings which automatically expand

to larger string when used in Insert Mode ( use .vimrc for permanent changes )

• To add an abbreviation– :ab UW University of Delhi

(Now if in insert mode I enter UW it be expanded to University of Delhi on entering any non-alphanumeric character)

• To list currently defined abbreviations – :ab

• To disable / delete an abbreviation use the :unab command – :unab UW → clears the given abbreviation– :abc → clear all the set abbreviation

MAPPING• MAPPING → any key can be mapped as shortcut for command.

( For making permanent changes use .vimrc )

• To add a key map – :map – dd (it creates a key map that works in command mode)– :map! @ dd (it creates a key map that works in insert mode)

• To list currently defined map keys – :map– :map!

• To remove a keymap– :unmap -– :unmap @

USEFUL TIPS• Launch vi and begin editing <filename> at line 125

– # vi +125 <filename>

• Launch vi and edit multiple files– # vi <file1> <file2> (switch to next file using :n)

• Change case of character under cursor– ~ ( press tilde key at current cursor positon)

• Join the current line and the next line– J ( capital J in command mode )

• Remove null lines in the file– : g/^$/d

• List all occurrences of the word 'foo' with line numbers– :g/foo/#

• Read output from a Unix shell command into current text– :r !<command>

USEFUL TIPS• Get the line number of current cursor positon

– Ctrl + g

• Repeats the action performed by last command– . ( press . In command mode )

• Temporarily returns to the shell to perform shell commands– :sh ( Type exit to return to vi )

• Execute a command from vi editor ex mode – :! <command>

LEARNING MORE

• vi/vim built-in help

• :help topic

• :help

• Use :q to exit help

• vimtutor command

• NOTE → USERS WITH UIDs > 200 WHEN TYPE VI WILL GET VIM EDITOR ( Because of alias of vi )

?