The Vi Unix Editor is the standard UNIX command line editor and if you’re planning on doing some configuring of a Unix Server you will definitely need to use the VI editor especially when you’re running a Command Line only operating system.

This hub will go through the basics of using the Vi unix editor, opening, creating, saving and writing to a file as well as the different modes for the Vi Editor. I will also go through common problems people have with the Vi editor especially the annoying problem when logging into your server using a SSH client such as Putty, where you find that the backspace key doesn’t work or the arrow keys simply return letters.

I’ll also cover basic terminal modes and types and how to make sure the server’s terminal type and the putty terminal type match so that you have no problems accessing and editing files remotely on your server.

- Command mode – This is the basic mode of the Vi editor and can be accessed by opening a file using “vi file.conf”. Letters and combination of letters will be interpreted as commands.

- Insert Mode – The Insert mode as it sounds allows you to edit text and insert your own text into configuration files. Depending on how your Unix system is setup you can either navigate using the arrow keys and regular windows keyboard or use the following. Press the INSERT key on your keyboard to enter this mode.

- INSEERT IMAGE, ordinarily you can use the regular keyboard functions otherwise use these ones. Paste bigger list onto a copy code thingo

- Line Mode – The line mode can be entered by pressing ESC and then type colon (J

From here you can either save the file, save and quit , or quit without saving changes.

:wq write the file to disk and quit

:q! quit without saving any changes

:w! newfile write all lines from the entire current file into the file 'newfile', overwriting any existing newfile

:n,m w! newfile write the lines from n to m, inclusive, into the file newfile, overwriting any existing newfile

- Backspace function not working

- Arrow keys return A, B, C , alpha functions

- Keys generally acting strange and muddled

- Errors when using Putty or SSH client to remotely access server

Solution – Vim Editor **

There is an incredibly easy solution to this problem, instead of using the light weight Vi editor, instead use vim to edit your files. Simply type Vim “filename” to edit the files and you will notice all the regular functions are restored. You can backspace as usual and the arrows also work fine.

You can also choose to change the alias for vi to point to the vim editor in your bashrc profile. Follow the steps below

- Open up your terminal window , Command Line

- Type “vim ~/.bashrc” , create the file if it doesn’t already exist, or copy the file from your existing login directory

- At the end of the file type “alias vi=’vim’”

- Save and Quit

- Done

SSH client Putty Problem – Weird key functions, backspace not working

Solution – Make sure the Terminal mode on your server matches the Terminal mode used on the putty or ssh client. If they don’t match putty and the server won’t be able to agree on how to interpret keys and you may find it hard to carry out basic tasks.

Check what Terminal Mode you are running

Echo $SHELL or Echo $TERM

You can set the terminal type by typing “set term/device=vt100” replace vt100 with your chosen terminal mode. Vt100 is the most commonly used.

Check Terminal Mode on your SSH client (putty)

- Check terminal-type string and make sure they match

- Save your SSH client configuration

Note: If your problem is only to do with the backspace check the setting under keyboard and try using Backspace key , Control-H.

Setting the Backspace Key on Linux

stty erase ^v<press backspace key right after typing ^v>

(just incase you incorrectly assign the backspace key)