VIM is so cool

VIM is really cool, you can increase/decrease a number in the text directly by with CTRL-A and CTRL-X!

Adding and subtracting 

       *CTRL-A*
CTRL-A   Add [count] to the number or alphabetic character at
   or after the cursor.  {not in Vi}


       *CTRL-X*
CTRL-X   Subtract [count] from the number or alphabetic
   character at or after the cursor.  {not in Vi}

The CTRL-A and CTRL-X commands work for (signed) decimal numbers, unsigned
octal and hexadecimal numbers and alphabetic characters.  This depends on the
'nrformats' option.
- When 'nrformats' includes "alpha", Vim will change the alphabetic character
under or after the cursor.  This is useful to make lists with an alphabetic
index.
- When 'nrformats' includes "hex", Vim assumes numbers starting with '0x' or
'0X' are hexadecimal.  The case of the rightmost letter in the number
determines the case of the resulting hexadecimal number.  If there is no
letter in the current number, Vim uses the previously detected case.
- When 'nrformats' includes "octal", Vim considers numbers starting with a '0'
to be octal.  Other numbers are decimal and may have a preceding minus sign.
If the cursor is on a number, the commands apply to that number; otherwise
Vim uses the number to the right of the cursor.

For numbers with leading zeros (including all octal and hexadecimal numbers),
Vim preserves the number of characters in the number when possible.  CTRL-A on
"0077" results in "0100", CTRL-X on "0x100" results in "0x0ff".  Note that
when 'nrformats' includes "octal", decimal numbers with leading zeros are
impossible because they are indistinguishable from octal numbers.

The CTRL-A command is very useful in a macro.  Example: Use the following
steps to make a numbered list.

1. Create the first list entry, make sure it starts with a number.
2. qa      - start recording into buffer 'a'
3. Y      - yank the entry
4. p      - put a copy of the entry below the first one
5. CTRL-A    - increment the number
6. q      - stop recording
7. @a - repeat the yank, put and increment  times