Tuesday, 8 February 2011

Unix vi commands quick reference

General Notes:
1. Before practicing using this vi tutorial, type the following command followed by a   carriage return: :set showmode
2. vi is not VI. It is case sensitive!!! So make sure Caps Lock is OFF.
Requirements:
In order to work correctly the vi need correct terminal type (TERM) setting. The TERM setting depends on the type of terminal you have. Commonly used TERM types are vt100, vt220 and ANSI.  In most cases vt100 will work fine. In case vi is not able to understand the TERM you have given, it starts in open mode giving you a line by line display. Generally TERM is taken from .profile or /etc/profile, but can be set at the command line as:
$TERM=vt100
$export TERM
echo $TERM will display the current TERM set.

Starting and Ending VI
Starting VI
vi filename Edits filename starting at line1
vi -r filename Recover filename that was being edited when system crashed
vi + n filename Edits filename and places cursor at line n
vi + filename Edits filename and places cursor on last line
vi +/string filename Edits filename and places cursor on first occurrence of string
vi filename file2 Edits filename, then edits file2 … After the save, use :n
Ending VI
ZZ or :wq or : x Saves and exits VI
:w Saves current file but doesn’t exit
:w! Saves current file overriding normal checks but doesn’t exit
:w file Saves current as file but doesn’t exit
:w! file Saves to file overriding normal checks but doesn’t exit
:n,mw file Saves lines n through m to file
:n,mw >>file Saves lines n through m to the end of file
:q Quits VI and may prompt if you need to save
:q! Quits VI and without saving
:e! Edits file discarding any unsaved changes (revert to previous saved version)
:e file Edits file (current file becomes alternate file)
:e# Edit alternate file
:we! Saves and continues to edit current file
% Display current filename
# Display alternate filename
:n Edit next file
:n! Edit next file (ignoring warnings)
:n files Specify new list of files
:r file Insert(read) file after cursor
:r !command Run command, and insert output after current line

Determining Line Numbers
:.= 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 total number of lines,
in the file at the bottom of the screen
Modes
Vi has two modes: 1) Insertion mode and 2) command mode.The editor begins in command mode, where the cursor movement and text deletion and pasting occur. Insertion mode begins upon entering an insertion or change command. [ESC] returns the editor to command mode (where you can quit, for example by typing: q!).
Most commands execute as soon as you type them except for “colon” commands which execute when you press the return key.
Inserting, appending and replacing Text
Inserting and appending text
I Inserts text at the beginning of the current line
i Inserts text at the cursor
A Appends text at the end of current line
a Appends text after the cursor
Adding new line
O Open a new line above the current line
o Open a new line below the current line
Replacing a character & word
R Replace characters, starting with current cursor position, until hit
r Replace single character under cursor (no needed)
cw Replaces the word from cursor to the end indicated by $ sign
C Replaces till end of line
:r file Reads file and inserts it after current line
:nr file Reads file and inserts it after line n
Things to do while in Insert Mode:
CTRL-h or Backspace While inserting, deletes previous character
CTRL-w While inserting, deletes previous word
CTRL-x While inserting, deletes to start of inserted text
CTRL-i or TAB While inserting, inserts one shift width(tab)
CTRL-v char While inserting, ignores special meaning of char (e.g., for inserting characters like ESC and CTRL) until ESC is used
CTRL-v Take the next character literally. (i.e. To insert a Control-H, type Control-v Control-h)
Motion
h or or [left-arrow] Moves the cursor to the left
j or or [down-arrow] Moves down the cursor
k or [up-arrow] Moves up the cursor
l or or [right-arrow] Moves the cursor to the right
Arrow Keys These do work, but they may be too slow on big files. Also may have unpredictable results when arrow keys are not mapped correctly in client.
w Moves cursor to the beginning of the next word
W Moves the cursor to next blank delimited word
b Moves the cursor back to beginning of the preceding word
B Moves the cursor to the beginning of blank delimited word
^ Moves the cursor to the first non-blank character in the current line
+ or Enter Moves the cursor to the beginning of the next line
- Moves the cursor to the first non-blank character of the previous line
e Moves  cursor to the end of the current word
E Moves cursor to the end of Blank delimited word
( Moves cursor a sentence back
) Moves cursor a sentence forward
{ Moves cursor a paragraph back
} Moves cursor a paragraph forward
[[ Moves cursor a section back
]] Moves cursor a section forward
0 or | Moves cursor to the start of the current line
N| Moves cursor to the column n in the current line
$ Moves cursor to the end of the current line
1G or :0 Moves cursor to the start of the first line in the file
G or :$ Moves cursor to the start of the last line in the file
nG or :n Moves cursor to the start of the nth line in the file
F Moves cursor forward to c
Fc Moves cursor back to c
H Moves cursor to the first line on the screen, or “home”
nH Moves cursor to nth line from the top of the screen
M Move cursor to the middle line on the screen
L Move cursor to the last line on the screen
nL Moves cursor to nth line from the bottom of the screen
CTRL-d Moves down ½ screen
CTRL-f Moves forward one full screen
CTRL-u Moves up ½ screen
CTRL-b Moves backward one full screen
CTRL-e Moves screen up one line
CTRL-y Moves screen down one line
CTRL-l Clears and redraws the current screen
CTRL-r Redraws the screen, removing deleted lines
CTRL-T Moves cursor to next tab position
CTRL-W Moves back one word
Z z-carriage return makes the current line the top line on the page
Nz Makes the line n the top line on the page
z. Makes the current line the middle line on the page
Nz. Makes the line n the middle line on the page
z- Makes the current line the bottom line on the page
Nz- Makes the line n the bottom line on the page
% Move to associated ( ), { }, [ ]
Deleting Text
Almost all deletion commands are performed by typing d followed by a motion. For example, dw deletes a word. A few other deletes are:
x Delete character to the right of cursor
nx Deletes n characters starting with current; omitting n deletes current character only
X Delete character to the left of cursor
nX Deletes previous n characters; omitting n deletes previous character only
D Delete to the end of the line
D$ Deletes from the cursor to the end of the line
dd or :d or CTRL-U Delete current line
ndw Deletes the next n words starting with current
ndb Deletes the previous n words starting with current
ndd Deletes n lines beginning with the current line
:n,md Deletes lines n through m
dMotion_cmd Deletes everything included in the Motion Command (e.g., dG would delete from current position to the end of the file, and d4 would delete to the end of the fourth sentence).
“np Retrieves the last nth delete (last 9 deletes are kept in a buffer)
“1pu.u. Scrolls through the delete buffer until the desired delete is retrieved (repeat u.)
Yanking Text
Like deletion, almost all yank commands are performed by typing y followed by a motion. For example, y$ yanks to the end of the line. Two other yank commands are:
yy Yank the current line
:y Yank the current line
nyy or nY Places n lines in the buffer-copies
yMotion_cmd Copies everything from the curser to the Motion Command (e.g., yG would copy from current position to the end of the file, and y4 would copy to the end of the fourth sentence)
“(a-z)nyy or “(a-z)ndd Copies or cuts (deletes) n lines into a named buffer a through z; omitting n works on current line
Changing text
The change command is a deletion command that leaves the editor in insert mode. It is performed by typing c followed by a motion. For example cw changes a word. A few other change commands are:
C Change to the end of the line
cc or S Change the whole line until ESC is pressed
xp Switches character at cursor with following character
stext Substitutes text for the current character until ESC is used
cwtext Changes current word to text until ESC is used
Ctext Changes rest of the current line to text until ESC is used
cMotion_cmd Changes to text from current position to Motion Command until ESC is used
<< or >> Shifts the line left or right (respectively) by one shift width (a tab)
N<< or n>> Shifts n lines left or right (respectively) by one shift width (a tab)
<Motion_cmd or >Motion_cmd Use with Motion Command to shift multiple lines left or right
Putting text
p Put after the position or after the line
P Put before the position or before the line
“(a-z)p or “(a-z)P Pastes text from a named buffer a through z after or before the current line

Buffers

Named buffers may be specified before any deletion, change, yank or put command. The general prefix has the form “c where c is any lowercase character. For example, “adw deletes a word into buffer a. It may thereafter be put back into text with an appropriate “ap.
Markers
Named markers may be set on any line in a file. Any lower case letter may be a marker name. Markers may also be used as limits for ranges.
mc Set marker c on this line
‘c Go to beginning of marker c line.
‘c Go to first non-blank character of marker c line.
Search for strings
/string Search forward for string
?string Search back for string
n Search for next instance of string
N Search for previous instance of string
% Searches to beginning of balancing ( ) [ ] or { }
fc Searches forward in current line to char
Fc Searches backward in current line to char
tc Searches forward in current line to character before char
Tchar Searches backward in current line to character before char
?str Finds in reverse for str
:set ic Ignores case when searching
:set noic Pays attention to case when searching
:n,ms/str1/str2/opt Searches from n to m for str1; replaces str1 to str2; using opt-opt can be g for global change, c to confirm change (y to acknowledge, to suppress), and p to print changed lines
& Repeats last :s command
:g/str/cmd Runs cmd on all lines that contain str
:g/str1/s/str2/str3/ Finds the line containing str1, replaces str2 with str3
:v/str/cmd Executes cmd on all lines that do not match str
, Repeats, in reverse direction, last / or ? search command
Replace
The search and replace function is accomplished with the :s command. It is commonly used in combination with ranges or the :g command (below).
:s/pattern/string/flags Replace pattern with string according to flags.
G Flag – Replace all occurrences of pattern
C Flag – Confirm replaces.
& Repeat last :s command
Regular Expressions
. (dot) Any single character except newline
* zero or more occurrences of any character
[...] Any single character specified in the set
[^...] Any single character not specified in the set
\< Matches beginning of word
\> Matches end of word
^ Anchor – beginning of the line
$ Anchor – end of line
\< Anchor – beginning of word
\> Anchor – end of word
\(…\) Grouping – usually used to group conditions
\n Contents of nth grouping
\ Escapes the meaning of the next character (e.g., \$ allows you to search for $)
\\ Escapes the \ character
[...] – Set Examples
[A-Z] The SET from Capital A to Capital Z
[a-z] The SET from lowercase a to lowercase z
[0-9] The SET from 0 to 9 (All numerals)
[./=+] The SET containing. (dot), / (slash), =, and +
[-A-F] The SET from Capital A to Capital F and the dash (dashes must be specified first)
[0-9 A-Z] The SET containing all capital letters and digits and a space
[A-Z][a-zA-Z] In the first position, the SET from Capital A to Capital Z
In the second character position, the SET containing all letters
[a-z]{m} Look for m occurrences of the SET from lowercase a to lowercase z
[a-z]{m,n} Look for at least m occurrences, but no more than n occurrences of the SET from lowercase a to lowercase z
Regular Expression Examples
/Hello/ Matches if the line contains the value Hello
/^TEST$/ Matches if the line contains TEST by itself
/^[a-zA-Z]/ Matches if the line starts with any letter
/^[a-z].*/ Matches if the first character of the line is a-z and there is at least one more of any character following it
/2134$/ Matches if line ends with 2134
/\(21|35\)/ Matches is the line contains 21 or 35
Note the use of ( ) with the pipe symbol to specify the ‘or’ condition
/[0-9]*/ Matches if there are zero or more numbers in the line
/^[^#]/ Matches if the first character is not a # in the line
Notes:
1. Regular expressions are case sensitive
2. Regular expressions are to be used where pattern is specified
Counts
Nearly every command may be preceded by a number that specifies how many times it is to be performed. For example, 5dw will delete 5 words and 3fe will move the cursor forward to the 3rd occurrence of the letter e. Even insertions may be repeated conveniently with this method, say to insert the same line 100 times.
Ranges
Ranges may precede most “colon” commands and cause them to be executed on a line or lines. For example :3,7d would delete lines 3-7. Ranges are commonly combined with the :s command to perform a replacement on several lines, as with :.,$s/pattern/string/g to make a replacement from the current line to the end of the file.
:n,m Range – Lines n-m
:. Range – Current line
:$ Range – Last line
:’c Range – Marker c
:% Range – All lines in file
:g/pattern/ Range – All lines that contain pattern
Shell Functions
:! Cmd Executes shell command cmd; you can add these special characters to indicate:% name of current file# name of last file edited
!! cmd Executes shell command cmd, places output in file starting at current line
:!! Executes last shell command
:r! cmd Reads and inserts output from cmd
:f Displays the name of the current file
:f file Renames current file to file
:w !cmd Sends currently edited file to cmd as standard input and execute cmd
:cd dir Changes current working directory to dir
:sh Starts a sub-shell (CTRL-d returns to editor)
:so file Reads and executes commands in file (file is a shell script)
!Motion_cmd Sends text from current position to Motion Command cmd
!}sort Sorts from current position to end of paragraph and replaces text with sorted text
Files
:w file Write to file
:r file Read file in after line
:n Go to next file
:p Go to previous file
:e file Edit file
!!program Replace line with output from program
VI Settings
Note: Options given are default. To change them, enter type :set option to turn them on or :set nooptioni to turn them off. To make them execute every time you open VI, create a file in your HOME directory called .exrc and type the options without the colon (:) preceding the option
:set ai Turns on auto indentation
:set all Prints all options to the screen
:set ap Prints line after d c J m :s t u commands
:set bf Discards control characters from input
:set dir=tmp Sets tmp to directory or buffer file
:set eb Precedes error messages with a bell
:set ic Ignores case when searching
:set lisp Modifies brackets for Lisp compatibility.
:set list Shows tabs (^l) and end of line ($)
:set magic Allows pattern matching with special characters
:set mesg Allows others to send messages
:set nooption Turns off option
:set nu Shows line numbers
:set opt Speeds output; eliminates automatic RETURN
:set prompt Prompts for command input with :
:set re Simulates smart terminal on dumb terminal
:set report Indicates largest size of changes reported on status line
:set ro Changes file type to “read only”
:set scroll=n set n lines for CTRL-d and z
:set sh=shell_path set shell escape (default is /bin/sh) to shell_path
:set showmode Indicates input or replace mode at bottom
:set sw=n Sets shift width to n characters
:set term Prints terminal type
:set terse Shorten messages with terse
:set timeout Eliminates one-second time limit for macros
:set tl=n Sets significance of tags beyond n characters (0 means all)
:set ts=n Sets tab stops to n for text input
:set wa Inhibits normal checks before write commands
:set warn Warns “no write since last change”
:set window=n Sets number of lines in a text window to n
:set wm=n Sets automatic wraparound n spaces from right margin.
Key Mapping
NOTE: Map allows you to define strings of VI commands. If you create a file called “.exrc” in your home directory, any map or set command you place inside this file will be executed every time you run VI. To imbed control characters like ESC in the macro, you need to precede them with CTRL-v. If you need to include quotes (“), precede them with a \ (backslash). Unused keys in vi are: K V g q v * = and the function keys.
Example (The actual VI commands are in blue):map v /I CTRL-v ESC dwiYou CTRL-v ESC ESC
Description: When v is pressed, search for “I” (/I ESC), delete word (dw), and insert “You” (iYou ESC). CTRL-v allows ESC to be inserted
:map key cmd_seq Defines key to run cmd_seq when pressed
:map Displays all created macros on status line
:unmap key Removes macro definition for key
:ab str string When str is input, replaces it with string
:ab Displays all abbreviations
:una str Unabbreviate str
Other
~ Toggle upper and lower case for the character at the current position
J Joins the line immediately below the current line with the current line
nJ Joins the next n lines together; omitting n joins the beginning of the next line to the end of the current line
. Repeat last text-changing command
U Undo the effect of last command (Note: u in combination with . can allow multiple levels of undo in some versions)
U Undo all changes to the current line
; Repeats last f F t or T search command

No comments:

Post a Comment

Number of Visitors