June 1, 1999 Vi Editor 1

Introduction to UNIX

C. Vi Editor

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Overview of vi

Performance Objectives1. Start/End VI (vi, ESC, :wq)

2. Move the Cursor and Window (h,j,k,l, ^f, ^b)

3. Insert, Change, Delete Text (i, a, x, dd)

4. Search and Replace text (/.../, :n, $s/.../.../g)

5. Move/Copy Text (ma, d'a, p)

6. Write and Read Files (:w file, :r file)

7. Tailor the VI Environment (:set)

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UNIX Family of editors

• ex line editor

• ed subset of ex

• vi screen editor

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Why learn vi/ex?

• Available on most UNIX systems.

• Works with a variety of terminals.

• Needs no special keyboard definition files.

• Allows the use of ex commands from vi.

• Provides for a customized editing environment.

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Some Conventions

• vi commands do not require a <CR>.

• vi commands not echoed.

• ex commands begin with : / ?

• ex commands are echoed and ended with a <CR>

• The character ^ represents the <ctrl> key.

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Vi Modes:

• COMMAND mode The default mode on entering vi. Anything typed is interpreted as a command.

• INSERT mode Enter INSERT mode by typing one of several

commands. Anything typed is interpreted as data. Exit INSERT mode by typing the <ESC> key.

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Vi Modes

UNIX Shellvi filename

Command Mode

i a o

Input Mode

<ESC>

ZZ or :wq

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vi Window Display

Line one Line twoLine three~~~~~~ Line n

Command line

File text

Null lines

EX cmd line

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Vi Window Positioning

File

vi window

^f Display Next segment

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Basic Window Positioning

• Move window forward 32 lines ^f

• Move window backward 32 lines ^b

• Move window forward one line ^e• Move window to line n of file :n• Move window to end of file G

• Move cursor up/dn left/rt or h j k l

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Making Changes Permanent

• vi uses a temp file for changes:

• Write file and quit editor :wq

• Undo last command: u or U

• Recovery: vi -r filename

TempFile

PermFile

:w

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Insert/Delete Functions

• Del current line dd

• Del current char x

• Insert before current char i ...

• Insert after current char a ...

• Insert after current line o ... (opens file at a line)

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More Vi Functions

• Open several files vi file1 file2 ...• End editor :q (does not save changes)• Redraw screen ^l (L)

• Join this line with next J

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Search For a Pattern

• Search forward to pattern / ... /

• Search backward to pattern ? ... ?

• Advance to next pattern n (forward or reverse)

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Replace A Pattern

• Replace string with another :s/.../.../ (only on same line)

• Replace string (global) :1,$s/.../.../g

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Moving Text

• ma mark the starting position with a

• d'a delete text into a buffer

• p put buffer contents after cursor

Area to be movedma

d’a

Insert locationp

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Copying Text

• ma mark the starting position with a

• y'a yank text into a buffer

• p put buffer contents after cursor

Area to be copiedma

y’a

Insert locationp

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Writing to a file

• write current file :w

• write named file :w filename

• overwrite named file :w!

• write lines m - n to named file m,nw file

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Useful Functions

• Re-edit current file, discard changes :e

• Edit named file :e file

• Read in and insert file at cursor :r file

• Execute command and return to vi :!cmd

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Tailoring the Environment• For current session :set options<cr>• Example: :set nu <cr> will set line numbers• To view possible settings:

:set all noautoindent nonumber noslowopenautoprint nonovice tabstop=8noautowrite nooptimize taglength=0nobeautify paragraphs= tags=tags /usr/lib/tagsdirectory=/tmp prompt term=vt100noedcompatible noreadonly notersenoerrorbells redraw timeoutflash remap ttytype=vt100hardtabs=8 report=5 warnnoignorecase scroll=11 window=23nolisp sections= wrapscannolist shell=/bin/csh wrapmargin=0magic shiftwidth=8 nowriteanymesg noshowmatchnomodelines noshowmode

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Order of Evaluation

• On startup, vi sets options defined by EXINIT variable.

• Then options defined in ~/.exrc file.

• Settings in ~/.exrc take precedence.

• Setting in .exrc file in CWD take precedence over ~/.exrc file and EXINIT.

• Finally, :set options of current session take precedence during that session.

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End of Module

Complete VI Editor Exercises