VI/VIM Text Editors

VI/VIM Overview• VI is an interactive text-based editor which can be used to

create and/or change files, it is the standard in UNIX systems for several decades.

• VI is hard to master but once mastered, it becomes a very powerful and quick editing tool.

• The Linux version is called VIM (VI Improved) which makes editing easier as it contains some in-editor navigation and editing tools which make the user’s life easier.

• Some alternatives to VI/VIM are: EMACS Pico Nano gedit

The VI Command• Once started, VI will fill the entire terminal screen until exited

and returned to the shell prompt.• VI is old, it originated from a predecessor called “ed” which

was used on printer terminals hence its commands and shortcuts are different than the keyboard shortcuts we know in modern systems, such as CTRL-[letter].

• Starting VI: vi [filename(s)] – enters the editor while editing the file(s) specified. view [filename(s)] – opens the file(s) in read-only mode. vi –r [filename] – recovers a crashed file.

VI Modes• VI has three work modes:

Insert mode – used for adding / editing text; hit ESC in insert mode to return to command mode.

Command mode – this is the default mode that VI enters once it is executed; the keys we hit will not be displayed on screen but this mode does allow us to use VI’s commands, which are short sequences of characters and key-combinations.

Last-line mode – displays a cursor in the bottom line of VI, allowing us to see the commands we type in; hit <CR> in order to return to command mode.

• Note that in order to move from Insert mode to Last-line mode, we must first pass through Command mode.

Insert Mode• In order to append or insert new text we can use one of the

following options: a – Append text after cursor. A – Append text at the end of the current line. i – Insert text before the cursor. I – Insert text at the beginning of the line. o – Open a new line below the cursor. O – Open a new line above the cursor.

• There are many ways to achieve the same goal so there is no need to remember all of the shortcuts.

Cursor Movement• VIM supports moving the cursor around with the keyboard

arrows; VI only allows arrow navigation in newer versions.• We can use the following alternatives to move around:

0 – go to the beginning of the line. $ - go to the end of the line. [n]G – jump to line number [n]. G – jump to last line in the file. gg – jump to the first line in the file. b – jump to the beginning of the word. e – jump to the end of the word. w – jump to the beginning of the next word. ^L – refresh the screen

• These are just some of the basic controls, there are many more.

Command Mode• Pressing ESC returns VI from insert to command mode.• Basic command structure in VI:

[count][command][scope]

• Let’s break down the command 10dw for example: 10 – this is the count of objects we wish the command to affect. d – “d” refers to delete. w – “w” is the scope, in this case – words.

• The above command will delete 10 words, beginning at the current location of the cursor.

Delete Commands• x – delete 1 character right of the cursor.• X – delete 1 character left of the cursor.• dd – delete the entire current line• dw – deletes to the beginning of the next word• d3l – deletes the next 3 characters. (l is lower-case L)• d0 – deletes to the beginning of the line.• d$ - deletes to the end of the line.• d1G – deletes to the beginning of the file.• dG – deletes to the end of the file.• D - deletes to the end of the line.

• Note that “d” commands delete to a buffer, as long as we have not quit VI we can always use undo/redo.

Change Commands• r – replace (overwrite) under the cursor.• R – enter Replace mode (overwrites any existing text)• cc – changes a complete line.• cw – changes to the beginning of the next word.• c3l – changes the next 3 characters.• c0 – changes to the beginning of the line.• c$ – changes to the end of the line.• c1G – changes to the beginning of the file.• cG – changes to the end of the file.• C – changes to the end of the line.

Cut, Copy & Paste Commands• y – yanks (copies) text to buffer• yy - yanks a complete line• yw – yanks to the beginning of the next word• y0 – yanks to the beginning of the line• y$ – yanks to the end of the line

• The “d” commands are used to cut text.

• p – paste everything in the buffer after the cursor location.• P – paste everything in the buffer before the cursor.

Misc Commands• u – undo last change• J – join current and next line• . – repeat last command• ~ - invert letter case and move on character to the right.• ZZ – Save changes and exit VI

Last-Line Mode• Search in VI:

/[pattern] – search forward for pattern matches ?[pattern] – search backwards for pattern matches n – repeat last search N – repeat last search in the opposite direction

• Search & Replace: :s/search-string/replace-with-string/g – this command will search for

“search-string” throughout the file and replace it with “replace-with-string”.

:10,20s/search-string/replace-with-string/g – same as above but the search will be performed only between lines 10 and 20.

:s/search-string/replace-with-string/gc – this command will search for “search-string” throughout the file and replace it with “replace-with-string” but ask for confirmation before each replacement.

File Commands• :r [filename] – read the file and place its contents under the

cursor.• :w – write (saves changes).• :w! – override write-protection mode and save changes.• :w [filename] – save into a file with the specific name.• :wq – save changes and quit VI• :x – save changes and quit VI• :q – quit without saving• :q! – force quit without saving• :![command] – execute a shell command• :r![command] – execute a shell command and place its output in the file

being edited.

VI Options• VI has many options that control its looks and behaviour.• For the full list of options, type: “:set all”• To enable an option, such as line numbering for example, use:

:set number

• To disable an options, use: :set nonumber

• The above rule is true for any one of VI’s options.