T HE VI EDITOR

vi has 2 modes: command mode (initial or "default" mode) insert mode [Esc] is used to switch to command mode. In general, vi commands: are case-sensitive are not shown on the screen when you type them do not require an [Enter] after the command.

O PEN A F ILE vi is working on a copy of your file in the buffer: your edits will not affect your original file until you save the buffer. $ vi [ filename ] If the filename is omitted, vi will open an unnamed buffer. A filename must be unique inside its directory. can include any ASCII character except a slash $ vi practice $ vi letter

S AVING /L OADING F ILE First check that you are in command mode by pressing [ESC] To save file and quit the vi: ZZ :w q To safe file without quitting vi: :w (write to specified file) :w (write again) :w! (to override existing file) To load existing file: :r To edit new file: :e

Q UITTING VI To return to the last saved version of the file: :e! [Enter] :q! [Enter] (with quitting from vi) vi normally won't let you throw away your edits. The exclamation point added to the :e or :q command causes vi to override this prohibition. To quit vi if no changes were made :q

M OVING THE C URSOR up k down j left h right l : 4l moves the cursor four spaces to the right, just as if you had typed l four times (llll) A line is any text entered between newlines. beginning of the current line 0 end of the current line $ :set nu (to display line numbers)

M OVING THE C URSOR BY B LOCKS To the next word w (symbols and punctuation as equivalent to words) W To the previous word b (symbols and punctuation as equivalent to words) B Movement commands take numeric arguments 4w, or 5B To the line number nn :nn nnG For example, :4 or 4G (goes to the 4 th line) To the last line :$

I NSERTING T EXT i inserts text before cursor. a appends text after cursor. A appends text to the end of current line. I inserts text at the beginning of line. With numeric prefixes, you might insert a row of underlines or alternating characters: 50i*[ESC] inserts 50 asterisks o opens blank line below cursor for text. O opens blank line above cursor for text. All of these commands leave you in insert mode. After inserting text, press [ESC] to escape back to command mode. J joins two consecutive lines. Using a numeric argument with J joins that number of consecutive lines: 3J.

C HANGING T EXT Command c replaces any text in your file specified by movement command: cw to the end of the current word c2b back two words c$ to the end of line c0 to the beginning of line c, like i and a, leaves you in insert mode until you press the [ESC]. General format of commands: ( command )( number )(movement command) ( number )( command )(movement command) Lines shortcuts cc changes an entire line. C is shortcut for c$. r replaces a single character with another single character. No [ESC]. R overstrikes existing characters with new characters. s ( S ) deletes character at cursor (line) and substitute text. ~ changes a case of letter. No number prefix or movement.

D ELETING T EXT Command d deletes any text in your file. d is combined with a movement command to specify what to delete: dw the current word d2b back two words d$ to the end of line d0 to the beginning of line Lines shortcuts dd deletes an entire line (2dd) D is shortcut for d$. x deletes a single character before the cursor. 5x deletes 5 characters before the cursor : d deletes lines in the range. Examples of the range are 1,$ 1,..,$ 5,12.,.+2

M OVING T EXT "cut and paste“ paradigm p puts the text in the buffer after the cursor position. P puts the text before the cursor. :nn, [Enter], p – to puts the text after nn position Once you delete text, you must restore it before the next change command or delete command; otherwise, deleted text will be lost. Transposing Two Letters : xp (delete character and put after cursor command) transposes two letters. There is no command to transpose words.

C OPYING T EXT A yank command ( y ) copies the selected text into a buffer. You can then place this copy elsewhere in the file with the p command. y can be combined with any movement command ( yw, y$, 4yy ). The shortcut yy, Y operates on an entire line. : y yanks lines in the range. Yanking uses the same buffer as deleting. Each new deletion or yank replaces the previous contents of the yank buffer.

R EPEATING OR U NDOING Y OUR L AST C OMMAND. (period) repeats last editing command. Position the cursor where you want to repeat the editing command, and type a period. Occasionally, vi has problems repeating a command. u undoes your last command.The cursor need not be on the line where the original edit was made. U undoes all edits on a single line, as long as the cursor remains on that line. Once you move off a line, you can no longer use U. pu uu

S CROLLING Ctrl+D down half screen Ctrl+U up half screen Ctrl+F forward one screen Ctrl+B back one screen Ctrl+L refresh screen (useful in telnet) z[Enter] moves current line to top of thescreen and scroll. z understands a numeric prefix as a line number that it will use in place of the current line.

S EARCHING The search command is the special character / (slash): / pattern[Enter] A pattern can be any sequence of characters. vi begins the search at the cursor and searches forward, wrapping around to the start of the file if necessary. To begin a search backward: ? pattern[Enter] n repeats search in the same direction. N Repeat search in opposite direction. / [Enter] repeats search forward. ? [Enter] repeats search backward.

S EARCHING /R EPLACING : s/string to change/desired string substitutes first occurence : s/string to change/desired string/g substitutes all occurences in the range You can also use % instead of 1,$ to specify every line in a file. If you'd like to confirm each replacement before it is made, add the c option (for confirm) at the end of the substitute command: : s/string to change/desired string/gc If you want to make the replacement, you must enter y (for yes) and press [Enter]; otherwise, simply press [Enter].