Basic vi Commands [zz]

Basic vi Commands

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What is vi?

The default editor that comes with theUNIX operating system is called vi (visual editor).[Alternate editors for UNIX environments include picoand emacs, a product of GNU.]

 

The UNIX vi editor is a full screen editor and has two modes of operation:

1. Command mode commandswhich cause action to be taken on the file, and
2. Insert mode in which entered text is inserted into the file.

In the command mode, every character typed is a command that doessomething to the text file being edited; a character typed in thecommand mode may even cause the vi editor to enter theinsert mode.In the insert mode, every character typed is added to the textin the file; pressing the <Esc> (Escape) keyturns off the Insert mode.

 

While there are a number of vi commands, just a handfulof these is usually sufficient for beginning vi users.To assist such users, this Web pagecontains a sampling of basic vi commands. The most basic and useful commands are marked with an asterisk(* or star) in the tables below.With practice, these commands should become automatic.

 

NOTE: Both UNIX and vi are case-sensitive.Be sure not to use a capital letter in place of a lowercaseletter; the results will not be what you expect.

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To Get Into and Out Of vi

 

To Start vi

 

To use vi on a file, type in vi filename. Ifthe file named filename exists, then the first page (or screen)of the file will be displayed; if the file does not exist, then anempty file and screen are created into which you may enter text.

 

*vi filename edit filename starting at line 1  vi -r filename recover filename that was beingedited when system crashed

 

To Exit vi

 

Usually the new or modified file is saved when youleave vi. However, it is also possible to quitvi without saving the file.

 

Note: The cursor moves to bottom of screen whenever acolon (:) is typed. This type of command is completed byhitting the <Return> (or <Enter>) key.

 

*:x<Return> quit vi, writing out modified fileto file named in original invocation  :wq<Return> quit vi, writing out modified fileto file named in original invocation  :q<Return> quit (or exit) vi *:q!<Return> quit vi even though latest changeshave not been saved for this vi call

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Moving the Cursor

 

Unlike many of the PC and MacIntosh editors, the mouse does notmove the cursor within the vi editor screen (or window). You must use thethe key commands listed below. On some UNIX platforms, the arrow keysmay be used as well; however, since vi was designed withthe Qwerty keyboard (containing no arrow keys) in mind, the arrowkeys sometimes produce strange effects in vi and shouldbe avoided.

 

If you go back and forth between a PC environment and a UNIXenvironment, you may find that this dissimilarity in methods forcursor movement is the most frustrating difference between the two.

 

In the table below, the symbol ^ before a letter meansthat the <Ctrl> key should be held down while theletter key is pressed.

 

*j or <Return>
  [or down-arrow] move cursor down one line *k [or up-arrow] move cursor up one line *h or <Backspace>
  [or left-arrow] move cursor left one character *l or <Space>
  [or right-arrow] move cursor right one character *0 (zero) move cursor to start of current line(the one with the cursor) *$move cursor to end of current line  wmove cursor to beginning of next word  bmove cursor back to beginning of preceding word  :0<Return> or 1G move cursor to first line in file  :n<Return> or nG move cursor to line n  :$<Return> or G move cursor to last line in file

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Screen Manipulation

 

The following commands allow the vi editor screen (or window) tomove up or down several lines and to be refreshed.

 

 ^f move forward one screen  ^b move backward one screen  ^d move down (forward) one half screen  ^u move up (back) one half screen  ^l redraws the screen  ^r redraws the screen, removing deleted lines

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Adding, Changing, and Deleting Text

 

Unlike PC editors, you cannot replace or delete text by highlighting it withthe mouse. Instead use the commands in the following tables.

 

Perhaps the most important command is the one that allows youto back up and undo your last action. Unfortunately, thiscommand acts like a toggle, undoing and redoing your most recentaction. You cannot go back more than one step.

 

*u UNDO WHATEVER YOU JUST DID; a simple toggle

 

The main purpose of an editor is to create, add, or modify textfor a file.

 

Inserting or Adding Text

 

The following commands allow you to insert and add text.Each of these commands puts the vi editor into insert mode;thus, the <Esc> key must be pressed to terminate theentry of text and to put the vi editor back into command mode.

 

*i insert text before cursor, until <Esc> hit  I insert text at beginning of current line,until <Esc> hit *a append text after cursor, until <Esc> hit  A append text to end of current line,until <Esc> hit *o open and put text in a new line below current line,until <Esc> hit *O open and put text in a new line above current line,until <Esc> hit

 

Changing Text

 

The following commands allow you to modify text.

 

*r replace single character under cursor(no <Esc> needed)  R replace characters, starting with current cursor position,until <Esc> hit  cw change the current word with new text,
starting with thecharacter under cursor, until <Esc> hit  cNw change N words beginning with character under cursor,until <Esc> hit;
  e.g., c5w changes 5 words  C change (replace) the characters in the current line,until <Esc> hit  cc change (replace) the entire current line, stopping when <Esc> is hit  Ncc or cNc change (replace) the next N lines,starting with the current line,
stopping when <Esc> is hit

 

Deleting Text

 

The following commands allow you to delete text.

 

*x delete single character under cursor  Nx delete N characters, starting with character under cursor  dw delete the single word beginning with character under cursor  dNw delete N words beginning with character under cursor;
  e.g., d5w deletes 5 words  D delete the remainder of the line,starting with current cursor position *dd delete entire current line  Ndd or dNd delete N lines, beginning with the current line;
  e.g., 5dd deletes 5 lines

 

Cutting and Pasting Text

 

The following commands allow you to copy and paste text.

 

 yy copy (yank, cut) the current line into the buffer  Nyy or yNy copy (yank, cut) the next N lines, including the current line,into the buffer  p put (paste) the line(s) in the buffer into thetext after the current line

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Other Commands

 

Searching Text

 

A common occurrence in text editing is to replace one word orphase by another. To locate instances of particular sets of characters(or strings), use the following commands.

 

 /string search forward for occurrence of string in text  ?string search backward for occurrence of string in text  n move to next occurrence of search string  N move to next occurrence of search string in oppositedirection

 

Determining Line Numbers

 

Being able to determine the line number of the current lineor the total number of lines in the file being edited is sometimesuseful.

 

 :.= returns line number of current line at bottom of screen  := returns the total number of lines at bottom of screen  ^g provides the current line number, along with the totalnumber of lines,
in the file at the bottom of the screen

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Saving and Reading Files

These commands permit you to input and output files otherthan the named file with which you are currently working.

 

 :r filename<Return> read file named filename and insert aftercurrent line
(the line with cursor)  :w<Return> write current contents to file named in original vi call  :w newfile<Return> write current contents to a new file named newfile  :12,35w smallfile<Return> write the contents of the lines numbered 12 through 35to a new file named smallfile  :w! prevfile<Return> write current contents over a pre-existing filenamed prevfile

 

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http://www.cs.colostate.edu/helpdocs/vi.html