viTricks every lazy C/C++ programer should know

1. You can run any shell command without leaving vi by typing:

        :! command 
   

   This will run a.out:

           :! a.out
   

   This will compile the program z.c:

           :! cc z.c
   

2. You can use % as a shorthand reference to the current file. This will compile the file you are editing:

           :! cc %
   

3. You can repeat the last shell command you entered (good for repeated compiles):

           :!!
   

4. You can compile the current file and place error messages in a file list

           :! cc % 2> err_lst
   

5. You can move back and forth between two files easily. If you are in file a , and want to edit file b enter :e b . Now you want to go back to file a enter :e # . This is useful if you place the compilation errors on the file err_lst (see above) and want to go back and forth between your file and the error file.

• the show match option allows one to check check nexting of parenthesis and and braces. Enter

          :set showmatch 
          
  

  and type the following

          while ( blah blah blah ) {
              do this loop }
          
  

  When you type the closing parenthesis or closing brace you should see the cursor jump to the opening parenthesis or brace. Next place the cursor at one of the parens or braces, and press the % key. The cursor should jump to the matching paren or brace. (also works for square brackets).

• the shiftwidth options allows one to easily indent blocks of code. enter

          :set shiftwidth=4
          
  

  Now at any line enter >> ; the line should be shifted 4 spaces; enter 3<< and the 3 lines at the cursor should be shifted 4 spaces. This is useful for increasing the indentation of a block of code.

• the tabstop option allows one to tab over when in insert mode. Enter the command

      :set tabstop=4
      
  

  and pressing the tab key in insert mode will move the code over 4 spaces
• Most programmers like tab stops of 4, but the rest of the world use tab stops of 8. If we wish to communicate with the rest of the world, (i.e. send code over email and have it look reasonable) it would be a good idea to remove the tabs, replacing all tabs with spaces. The command that does this from the shell is:

          pr -t -e4 file.c > file.txt
      
  

• It is too much trouble to set all the options everytime we login. In your home directory name .exrc and put in it

      :set showmatch
      :set shiftwidth=4
      :set tabstop=4
      
  

  Everytime vi starts up, it looks for this file and executes all commands in it
• How to cut and paste from a terminal
  Suppose you had some text like

      while  (a > 0 ) {
          do thing
          
      }
      .....
      more stuff
      .....
  

  and you wanted to copy the while loop after the more stuff. There are several ways to do the; the more general way may
  1. mark the while loop. Place the cursor at line including the enter :ma (create marker a at current position )
  2. move cursor to end of while loop and enter :mb create a marker at the end of while loop
  3. enter 'a (that's apostrophe a) to move to marker a
  4. enter "aY'b This will copy the text between the between the current postion and 'b into a buffer called a
  5. move the cursor to were you want to place the while loop, i.e. after more stuff.
  6. enter "aP this will put what's in buffer a into current position.
• You can move text from file a to file b . Suppose you want to place the while loop into another file. Copy the while loop into the buffer a as above, move to the to file b , and paste the while loop into the file.
• This command will replace the 3rd character from the end of each and every line with '::' (nothing else will be changed). Try doing this in Word!

  1,$s/.\(..\)$/::\1