http://amath.colorado.edu/computing/unix/vi/

Using the VI editor
(the very basics)

The VI editor is a screen-based text editor available on all Unix computers (and available for all other kinds of computers, sometimes as « vim » rather than « vi »). Given that it takes some effort, why bother to learn VI? Because

• sometimes it’s the only available editor
• when you log on remotely (ssh) to a Unix host from a Mac or PC, only a text editor (like VI or emacs or pico) can be used to edit files in a text-only terminal window
• mouse movements (e.g., menus, highlighting, clicking, scrolling) slow down the touch-typist. VI requires none
• as mentioned above, VI is the editor sure to be on every Unix computer in the world
• VI is a very powerful editor for those who learn more than just the beginner commands, and even more powerful for those who are familiar with Unix commands

If you will be using Unix/Linux computers, especially via ssh, save yourself headaches and learn the basics of VI now! This web page (and the 2-page PDF summary) are for reference; for a hands-on tutorial type the Unix command « vitutor » or « vilearn », or try the hyperlinks at the top of this page.

In the following, ^X denotes a control character. For example, « ^D » means to hold down the Control key and press the « d » key. Also « Rtn » means to press the Return (or Enter) key, while « Esc » means to press the Escape key, located in the far upper left corner of the keyboard.

1. Starting: To edit a file named (say) « mytext » on a Unix computer, type the command « vi mytext ». Note that you must type the command with lowercase letters.

2. Two Modes: Pay attention, this is the crucial feature of VI!   There are two modes, command and insert. When in insert mode, everything you type appears in the document at the place where the blinking cursor is.   When in command mode, keystrokes perform special functions rather than actually inserting text to the document. (This makes up for the lack of mouse, menus, etc.!)   You must know which keystroke will switch you from one mode to the other:

• Switch to insert mode:                     press   i               (or  a,  or  o)
• Switch to command mode:             press   Esc

3. Getting out:  When you want to get out of the editor, switch to command mode (press Esc) if necessary, then

• type     :wq Rtn            to save the edited file and quit
• type     :q! Rtn              to quit the editor without saving changes
• type     ZZ                      to save and quit (a shortcut for :wq Rtn)
• type     :w filename       to save the edited file to new file « filename »

4. Moving Around:  When in command mode you can use the arrow keys to move the cursor up, down, left, right.  In addition, these keystrokes will move the cursor:

5. Inserting Text: From command mode, these keystrokes switch you into insert mode with new text being inserted

6. Cutting, Copying, Pasting: From command mode, use these keystroke (or keystroke-combination) commands for the described cut/copy/paste function:

• x          delete (cut) character under the cursor
• 24x    delete (cut) 24 characters
• dd       delete (cut) current line
• 4dd    delete (cut) four lines
• D          delete to the end of the line from the cursor
• dw       delete to the end of the current word
• yy       copy (without cutting) current line
• 5yy    copy (without cutting) 5 lines
• p          paste after current cursor position/line
• P          paste before current cursor position/line

7. Searching for Text: Instead of using the « Moving Around » commands, above, you can go directly forward or backward to specified text using « / » and « ? ».  Examples:

• /wavelet Rtn        jump forward to the next occurrence of the string « wavelet »
• ?wavelet Rtn        jump backward to the previous occurrence of the string « wavelet »
• n                                repeat the last search given by « / » or « ? »

8. Replacing Text: This amounts to combining two steps; deleting, then inserting text.

• r          replace 1 character (under the cursor) with another character
• 8r       replace each of the next 8 characters with a given character
• R          overwrite;  replace text with typed input, ended with Esc
• C          replace from cursor to end of line, with typed input (ended with Esc)
• S          replace entire line with typed input (ended with Esc)
• 4S       replace 4 lines with typed input (ended with Esc)
• cw       replace (remainder of) word with typed input (ended with Esc)

9. Miscellany: The commands on these two pages are just the start. Many more powerful commands exist in VI, especially those which invoke other Unix text-filtering commands (sort, fmt, uniq, cat, sed, awk, grep, etc.). More complete descriptions of all the possible commands are available on the web; see the list of VI manuals/tutorials maintained at The Vi Lovers Home Page or use a generic web search to search for « vi tutorial » or « vim tutorial ».

Some useful or spectacular « miscellaneous » commands (not in categories 1-8 above):