Question

How do I check if a selection has EOL spaces and remove them only if there are?

I need to remove the EOL spaces of a selection in order to do an other operation.
I would like to check if there are but don’t know how to do this.

Answer 1

You can suppress errors in the :substitute command using the e flag.
So eckes’ suggestion would become:

:'<,'>s/\ \+$//ge

Then any errors are ignored, and scripts are not interrupted. See :help s_flags for more information.

If you really want to check if there are trailing spaces you could try using something like

if matchstr(getline("."),'\s\+$') == ""
    " there is no trailing whitespace
else
    " there is some trailing whitespace
endif