the vi editor

Introduction to the vi Editor

CONTENTS

• Description of the vi Editor
• Setting Environment Variables Used by vi
• Editing a New File
• Saving Your File
• The vi Command Repeat Factor
• Summary of the Most Frequently Used vi Commands
• Text Input Commands
• Moving Through Your File by Positioning the Screen
• Cursor Movement by Characters and Lines
• Cursor Movement by Words
• Moving by Sentence or Paragraph
• Shifting Text
• Deletion Commands
• Change Commands
• Undo Commands
• Save and Exit Commands
• Advanced vi Topics
  • ex Command Address
  • Marking Lines
  • Automatically Numbered Buffers
  • Named Buffers
• ex Deletion Commands
• Move, Copy, and Rearrangement Commands
• Incorporating a File or Parts of a File
• Placing Lines From the File You Are Editing Into Another File
• Searching and Substituting One String for Another String
  • Simple Search
  • Global Search
  • Special Characters Used in Search Strings
  • Matching Special Characters
  • Search and Substitute
  • Line Searches
• Miscellaneous Features
  • Displaying the Current Filename and Line Number
  • Refreshing the Screen
  • Changing Case
  • Transposing Characters
  • Matching Parentheses, Braces, or Brackets
  • Abbreviating Long Text Phrases
  • Recovering a File
  • Executing Shell Commands
  • Inserting Shell Output Into Your File
  • Read-only Mode
• The .exrc vi Startup File and Setting vi Parameters
• References

Please note that in order to view this page properly, you must use a Web browser which supports tables. For instance, Netscape V1.1 (or better) or Mosaic V2.6 for UNIX (or better).

This page provides an overview of the vi editor. Users learning vi should consider getting a textbook on vi, or a Unix textbook that describes vi. A list of Unix and Unix related texts is available.

The following symbols are used to represent special keys:

• <Ret> Return or Enter key
• <Esc> Escape key
• <Ctrl> Control key

Description of the vi Editor

vi is a standard Unix full-screen editor. vi stands for "visual editor" and is pronounced "vee eye". It is based on an underlying line mode editor called ex.

The vi editor has three modes: command, insert, and last line modes. When you first bring up vi, you are in command mode, where you can move the cursor around, delete or append text, type last line mode commands, or enter insert mode. When you are in insert mode, all you can do is insert text. You cannot move your cursor around while you are in insert mode (except that the cursor moves as you insert text, of course, and you can use your Delete key to delete characters you mistype). To return to command mode from insert mode, press the <Esc> key.

Last line mode is for commands beginning with: (the ex commands), as well as commands starting with /, ?, or !. Whenever you type a last line command, your cursor moves to the last line of your screen (which is why these commands are called last line commands).

vi commands are case sensitive; the a command, for example, is different from the A command. Sometimes, when vi seems to be behaving strangely, it is because your Caps lock (or Shift lock) key is turned on, and you are actually typing uppercase commands when you think you are typing lower case ones!

Setting Environment Variables Used by vi

Before using vi you need to tell the system what kind of terminal you are using. This is done by setting the environment variable TERM to your terminal type. If you are using the X Window system, your terminal type is usually either "xterm" or "xterms" (the latter is for Sun workstations with the Sun-enhanced version of X Windows). If you are using VT100 style terminal emulation, your terminal type is "vt100". If you can't get vi to work properly (for example, the lines at the top of the file you are editing scroll by really fast), try using vt100 as your terminal type.

You set environment variables for the Bourne, Korn, and POSIX shells in the .profile file. In addition to setting your TERM environment variable, you should also set the EDITOR environment variable to vi so that various system utilities know that your preferred editor is vi.

To set your default editor to vi, enter the following in your .profile:

EDITOR=vi; export EDITOR

If you are using X Windows, enter:

TERM=xterm; export TERM

For Sun workstations with the Sun-enhanced version of X Windows enter:

TERM=xterms; export TERM

For VT100 emulation, enter:

TERM=vt100; export TERM

You set environment variables for the C and Tenex C shells in the .login or .cshrc file. Traditionally, environment variables are set in the .login, but sometimes when you login to a computer using X Windows the .login is not executed. Therefore, it is safest to place the following commands in your .cshrc.

In the C shell, it is also necessary to let the system know your window size, if you are using X Windows. This is done by using the:

eval `resize`

command. Note that the `s in `resize` are back quotes.

The C shell equivalents for the above Bourne shell commands are:

setenv EDITOR vi

setenv TERM xterm; eval `resize`

setenv TERM xterms; eval `resize -s`

setenv TERM vt100

Editing a New File

To create a new file and start inserting text into it, type:

   vi filename<Ret>
   i

After typing the i, start typing the text you want to insert. Do not press the Return key after typing the i; just start typing your input text.

Return to command mode by typing <Esc>.

Saving Your File

To save your file and exit from vi, type the following (from command mode):

ZZ

Alternatively, type:

:wq<Ret>

As soon as you type the :, your cursor will move to the bottom of the screen. Continue typing wq<Ret>.

Some people say that using :wq<Ret> is safer than ZZ, but ZZ is easier! Normally, you shouldn't have problems using ZZ.

If you want to exit from vi without saving the changes you have made, type:

:q!<Ret>

The vi Command Repeat Factor

Many vi mode commands may be prefixed by a command repeat factor. This means that most character, change, delete, word, movement, and positioning commands may be preceded by a number which refers to the number of times the command should be repeated. For example, j moves the cursor 1 character down, and 4j moves the cursor 4 characters down. In the commands listed below, examples of using the repeat factor are shown by placing the character n in front of a vi mode command. Not all vi mode commands are shown with a repeat factor; just a few, to remind you that it exists!

Note that the repeat factor only works with vi mode commands; it does not work with ex commands (which are described later).

Summary of the Most Frequently Used vi Commands

You will be able to do much of your editing using the following commands. Once you are familiar with the list below, read through the rest of the article to pick up additional useful commands.

Text Input Commands

The following commands enter insert mode. To return to command mode, press the <Esc> key.

Moving Through Your File by Positioning the Screen

Note: <Ctrl> represents the Control key. <Ctrl>f means hold the Control key, then press the f key.

Cursor Movement by Characters and Lines

Note: If you moved away from a spot by using a search or G command, you can return to your previous location by typing two single quotes:

''

Cursor Movement by Words

In vi, a "word" is either a group of letters, digits and _; or a group of punctuation marks (including special characters other than _). For example:

   one            1 word:  one
   one!           2 words: one and !
   one!). Next    3 words: one and !). and Next
   one!). "Next   4 words: one and !). and " and Next

A "blank delimited word" (called WORD in the explanations below of commands that use it) includes adjacent punctuation. WORDs are separated by spaces, tabs or newlines (what you get when you type <Ret>). For example:

   one            1 WORD:  one
   one!           1 WORD:  one!
   one!). Next    2 WORDs: one!). and Next
   one!). "Next   2 WORDs: one!). and "Next

Moving by Sentence or Paragraph

In vi, a sentence ends with a ., !, or ?, followed by TWO BLANK SPACES (one blank space doesn't cut it!) or a newline (what you get when you type <Ret>). Paragraphs are separated by one or more blank lines.

Shifting Text

Note: The default tabstop is 8 characters. To change your tabstop, use the :set tabstop command, as explained below in the section called "The .exrc vi Startup File and Setting vi Parameters".

Deletion Commands

Change Commands

Change commands effectively insert data. With the exception of r, all the change commands listed below will put you in insert mode. To return to command mode use the <Esc> key.

Undo Commands

Save and Exit Commands

Advanced vi Topics

We now introduce the following more advanced vi topics:

• ex Command Addresses
• Marking Lines
• Automatic Numbered Buffers
• Named Buffers

ex Command Addresses

ex commands, those that begin with a : and are used in vi's "last line mode", are often used with an ex command address range to indicate which lines the ex command should be applied to. : commands are executed only after you press <Ret>. If you want to exit last line mode without executing a command, type <Ctrl>c (hold the Control key, then press the c key).

Remember that whenever you type a last line mode command, your cursor moves to the last line of the screen, where you type the rest of the command.

The following ex command deletes lines 10 through 25:

:10,25d<Ret>

The address in the above example is 10,25. The : indicates that this is an ex command, and d is the actual command (delete).

Some of the commonly used ex command addresses are:

For example, to delete the first line in the file through the current line, type:

:1,.d<Ret>

The following example would erase the contents of the file and leave it empty:

:%d<Ret>

Lines above or below the current line can be specified by a - or a + and may be used to designate a block of lines. The following example shows the 5 lines before and the 8 lines after the current line being deleted (the current line is deleted as well):

:-5,+8d<Ret>

Marking Lines

A marker is a pointer to a line or to a character in a line. There are 26 markers, one for each lowercase letter of the alphabet. The marked line (or character) is addressed by preceding its marker letter with a single quote.

The command ma marks the current cursor position with the letter a (where a can be any letter from a to z).

For example, to mark line number 15 with a "j" and line number 30 with an "a", move the cursor to line 15 and type:

mj

Then move the cursor to line 30 and type:

ma

Then, from anywhere within the text you can move the cursor to line 15, which has been marked with the letter j, by typing:

'j

Alternatively, you can use `j to go to the specific character where the cursor was located when you marked the line.

If you want to delete lines 15 through 30, you can type:

:'j,'ad<Ret>

An alternative way of deleting a block of lines is by:

1. Marking the bottom line of the block, with the letter k, say:

   mk

2. Moving the cursor to the top line of the block, and then

3. Typing:

   d'k

Automatically Numbered Buffers

There are nine buffers available to hold yanked or deleted text. The most recently deleted text is in buffer 1, the default buffer, and the oldest deleted text is in buffer 9 (the buffers are automatically recycled). Only the default buffer (buffer 1) is used for yanked text.

To retrieve text, a " (double quote, not two single quotes) precedes the buffer number and is followed by the p ("place the contents of the buffer in a new line created below the current line) or P ("place the contents of the buffer in a new line created above the current line) command. For example:

"2p

places the contents of buffer 2 below the current line.

P

places the contents of the default (most recent) buffer above the current line.

Named Buffers

There are 26 available named buffers using lowercase letters a through z. If you repeat the same buffer letter in a command, the most recently deleted or yanked text will replace the older text. The buffer is named by preceding its letter with a double quote (not two single quotes). For example,

"ayy

places the contents of the current line into buffer a (using the yy yank line command). You can then retrieve the contents of this buffer by typing:

"ap

Don't confuse marked lines with named buffers! Marked lines are indicated with ' or ` in commands; named buffers are indicated with ".

ex Deletion Commands

Move, Copy, and Rearrangement Commands

Incorporating a File or Parts of a File

The following sequence of commands shows how to incorporate part of a second file into the file you are currently editing.

Placing Lines From the File You Are Editing Into Another File

Searching and Substituting One String for Another String

Simple Search

The slash (/) is used to search forwards, and the question mark (?) to search backwards. Both / and ? are last line mode commands: when you type a / or a ? your cursor moves to the last line of the screen, where you type the rest of the search command. Search commands are executed only after you press <Ret>. If you want to exit last line mode without executing the search command, type <Ctrl>c.

Case is respected in searches unless you issue the ex command:

:set ignorecase<Ret>

which can be abbreviated:

:set ic<Ret>

The search will wrap around the end-of-file to the beginning-of-file or vice versa, depending on the direction of the search, unless you issue the ex command:

:set nowrapscan<Ret>

which can be abbreviated:

:set nows<Ret>

in which case the search will stop when it reaches the last line in its search direction.

To repeat the search in its original direction, type:

n

To reverse the direction of the original search, type:

N

Example of a forward search on the word greetings:

/greetings<Ret>

If the string is found, to search backward for the next occurrence, type:

N

Example of a backward search on the word greetings:

?greetings<Ret>

To continue searching backward, type:

n

Global Search

There are two global search commands, one (g) which includes the search string, and one (v) which excludes the search string. These search commands may be followed by edit commands, such as d to delete the line in which the search string appears or doesn't appear. For example:

:g/gimbel/d<Ret>

Deletes all lines that contain the string gimbel.

:v/gyre/d<Ret>

Deletes all lines that DO NOT contain the string gyre.

Special Characters Used in Search Strings

Some of the special characters that can be used within search strings are:

Matching Special Characters

The special characters ^, $, ., [, ], /, and \ must be preceded by a backslash to search for them specifically.

To search for a dollar sign ($), type:

/\$

To search for a backslash (\), type:

/\\

If you search for special characters a lot, you can turn off the special search meanings of . , [ , ] , /<, and /> by typing:

:set nomagic

^ and $ always retain their special search meanings, no matter whether you have "magic" or "nomagic" set.

Search and Substitute

The search and substitute command has two option flags: the g flag for making global changes, and the c flag for making conditional changes (these are described below). The format of the search and substitute command is:

:[address]s/search_string/replace_string/flags<Ret>

To search on the current line for the first occurrence of "may" and replace it by the word "will":

:s/may/will<Ret>

To change all of the occurrences of "may" to "will" on the current line, use the g (for global) flag:

:s/may/will/g<Ret>

In the following example, both the g and c flags are used. The g means global, and will cause all occurrences in lines 1 through 5 to be selected, instead of just the first occurrence in each line. The c means conditional, and means that you will be asked whether or not to make the substitution.

:1,5s/want/would like/cg<Ret>

Respond:

y<Ret>

for yes, or:

n<Ret>

for no (the default).

To replace all the words "blue" with the word "red" throughout the file:

:%s/blue/red/g<Ret>

The ampersand (&) is a special "metacharacter". If it is used in the replacement string, it keeps the search string as part of the replacement. For example, to change "red" to "red car":

:s/red/& car/<Ret>

To repeat the last replacement string, use a percent sign. If you have typed:

:s/car/great big beautiful limousine/<Ret>

then

:s/red/%/<Ret>

will change a new search string to the previous long replacement string.

Line Searches

Miscellaneous Features

Displaying the Current Filename and Line Number

Use <Ctrl>g to display the current filename and line number.

Refreshing the Screen

Use <Ctrl>l to clear and refresh the screen. This is useful when your screen gets cluttered by a message another user might write to you while you are in vi. While the screen does look messy when this happens, no harm has been done to your text (as you can verify by refreshing the screen with <Ctrl>l.

Changing Case

A tilde ( ~ ) typed at the cursor position will change uppercase to lower and vice versa. The following will also change case:

Transposing Characters

To transpose two characters at the cursor, type:

xp

Matching Parentheses, Braces or Brackets

If you place the cursor on a left or right parenthesis, left or right brace ({ or }), or left or right bracket ([ or ]), and type in the percent sign %, vi will move the cursor to the matching character of the pair.

Abbreviating Long Text Phrases

If you have a long phrase that is repeatedly used in your text, you can set up an abbreviation for it. When the abbreviation is used in insert mode, the full text will be substituted.

For example, when you are in command mode, to set up an abbreviation for "Really Terrific Foobar Manufacturing", type:

:abbr rtfm Really Terrific Foobar Manufacturing

Then, when you are in insert mode, if you type:

Thanks to.rtfm.

This will appear on your screen:

Thanks to.Really Terrific Foobar Manufacturing.

Note: Blanks may be substituted for the two periods in the above example, so that the expanded phrase will have a blank on either end. A non-alphabetic, non-numeric character must be used at the beginning and end of the abbreviation for expansion to occur.

The abbr command can be put in your .exrc file, in which case the leading colon, :, is omitted.

Recovering a File

If the system has crashed while you were editing a file with vi, you may be able to recover the file with:

vi -r filename<Ret>

To list recoverable files, type:

vi -r<Ret>

Executing Shell Commands

To execute a single shell command, type:

:!command<Ret>

To create a shell and execute multiple shell commands, type:

:sh<Ret>

To return to your vi session after executing the shell commands, type:

exit<Ret>

Inserting Shell Output Into Your File

Read-only Mode

You may want to scan the contents of a file without the ability to change it. To do this, you may use the read-only option. To enter vi in read-only mode, type:

vi -R filename<Ret>

or:

view filename<Ret>

The .exrc vi Startup File and Setting vi Parameters

You can set up your own editing environment by using a file named .exrc, which will be executed whenever you begin a vi editor session. The contents of the .exrc file consists of set and possibly other commands. The set command is used to set vi parameters. Some of the possible set commands are listed below.

For example, your .exrc file might consist of the following 4 lines:

• set showmode
• set number
• set wrapmargin=1
• set ignorecase

While editing a file with vi, to negate the number, showmode, warning, ignorecase, autoindent, or wrapscan settings, type:

Other :set commands that may be useful are:

To find out what options are currently set type:

References

The following were used as references in preparing this article:

• A Practical Guide to Unix System V by Mark G. Sobell
• Learning the vi Editor by Linda Lamb
• vi Reference by Maarten Litmaath (maart@cs.vu.nl)
• Cray man pages for vi and ed.

Links to this Page

• unix system docs last edited on 16 December 2014 at 4:49 pm by dhcp92.hfbk.net
• enter. last edited on 21 February 2002 at 1:43 am by max2-171.dialin.uni-hamburg.de.