in vim, with
I get the number of all buffers the same with
how I can get the total number of buffers ?
Same idea than Heptite's solution, but as a one liner. Many other things may be done this way: get the name of the buffer (thanks to map), wipeout buffers that match a pattern, http://stackoverflow.com/questions/2974192/how-can-i-pare-down-vims-buffer-list-to-only-include-active-buffers/2974600#2974600n etc.
To my knowledge there is no built-in method in Vim to do this, but you could create a function:
Put the above in a text file with its name ending in .vim, :source it, then you can do something like: