How could I remove trailing blank lines on save, in Vim?

Question

I want to remove trailing blank lines (blank lines could also be just a bunch of tabs and spaces).

In my .vimrc I have:

autocmd BufWritePre * :%s#\($\n\s*\)\+\%$## " trim white spaces at the end of file  

This works, however if a file has already had its trailing blank lines removed, I get the following error message:

Error detected while processing BufWrite Auto commands for "*":

How may I fix this?

Answer 1

From :help :s_flags:

[e]     When the search pattern fails, do not issue an error message.

So you could try:

:%s#\($\n\s*\)\+\%$##e