Unexpected behavior from cb command

Question

One of the most basic editing commands is c<motion> to change text, e.g. cw - change word, c$ - change to end of line, cc - change entire line, c3l - change 3 characters to the right.

My question is, why then does cb at the end of a word prepare for replacement, excluding the last character of the word (i.e. the character that the cursor was over when typing the command)?

vb at the end of a word will select the entire word, including the last character. Should cb not be expected to have the same behavior?

In short: The behavior of vbc is expected, but behavior of hvbc is equivalent to cb.

I'm using Vim 8.0.1350.

It seems this behavior follows more the idea that the cursor is "between" characters (insert mode) rather than "over" a character (normal mode).

Answer 1

The b motion is an exclusive motion. Visual mode is inclusive by default (See :h 'selection').

From :h exclusive:

A character motion is either inclusive or exclusive.  When inclusive, the
start and end position of the motion are included in the operation.  When
exclusive, the last character towards the end of the buffer is not included.
Linewise motions always include the start and end position.

You are using b when you probably want to use the iw text object instead, e.g. cb vs ciw. See :h iw and :h text-objects.

You can also force inclusivity on a motion by using v after an operator, e.g. cvb will do a change over motion b but inclusively. See :h o_v.

Answer 2

The other answer doesn’t give the full command (note the equals sign):

:set selection=inclusive

even though the default is supposed to be inclusive. On my debian box I had to add it to .vimrc because it was exclusive.