Basic VI

Tran, Van Hoai

Faculty of Computer Science and Engineering HCMC Uni. of Technology

hoai@cse.hcmut.edu.vn

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vi - always available

Default editor in UNIXcome along with all UNIXs

Original name is Visual EditorFull screen (on terminal)Some new variants with advanced operating

commands Basic commands implemented in all

variants of vi

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Operation modes

2 modescommand: receive actions on edited file insert: insert text into file

<ESC> to exit insert mode

UNIX and vi are case-sensitive

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Get in & out

* vi filename open file for editing

* :x<Return> write modified content and quit

:wq as above

:q just quit

* :q!<Return> quit without writing

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Moving the cursor

cannot use mouse designed for Qwerty keyboard, can use

non-arrow keys

* j,k,h,l down, up, left, right

0, $ beginning, end of current line

:0 first line of file

:$ last line of file

:n<Return> to line n

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Undo

* u undo last action

toggle the last action cannot go more than one step

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Insert and add text

put vi into insert mode Press <ESC> to exit insert mode

* i,a insert text before/after cursor, until <Esc> hit

A append text to end of current line, until <Esc> hit

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delete text

work in command mode

* x delete single character under cursor

* dd delete entire current line

D delete the remainder of the line, starting with current cursor position

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cut and paste

work in command mode

yy copy the current line into buffer

Nyy copy next N lines

p paste the buffer after the current line

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search text

work in command mode

/string search forward for occurrence of string in text

?string search backward for occurrence of string in text

:.= returns line number of current line at bottom of screen

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save and read files

:r filename<Return>

read file named filename and insert after current 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 35 to a new file named smallfile

:w! prevfile<Return>

write current contents over a pre-existing file named prevfile

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Replacing patterns (1)

Character Pattern

\ turn off special meaning

\n reuse the text matched by the nth subpattern previously saved by \( and \). Numbered from 1 to 9

& text match search pattern

~, % reuse previous replacement pattern

\u convert first character of replacement pattern to uppercase

\U convert entire replacement pattern to uppercase

\l, \L same; to lowercase

\e turn off previous \u or \l

\E turn off previous \U or \L

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Example (6)

Command Result

s/.*/( & )/ add space and parentheses

s/.*/mv & &.old/ ?

/^$/d delete blank lines (vi, g/^$/d for all lines)

%s/ */ /g turn one or more spaces into one space

%s/.*/\L&/ lowercase entire file

%s/yes/No/g replace yes to No

%s/Yes/~/g replace yes to No (previous replacement)

s/\(F\)\(ORTRAN\)/\1\L\2/g

FORTRAN to Fortran

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Applications

Pattern Matched text

grab a specific HTML tag

[0-9]\{1,3\}\. ???? IP address

Email address

Valid dates (day-month-year)

WeWe, does not match Wee

<TAG\b[^>]*>\(.*?\)</TAG>

[A-Z0-9._%-]+@[A-Z0-9.-]+\.[A-Z]{2,4}

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text processing utilities

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