This is a plugin for NERDTree to allow for chmod'ing files in Vim.

When opening the default file menu in NERDTree using <m>, you can hit <x> which
will allow you to chmod the file. Because I primarily use this to toggle whether
a file is executable or not, it will default to either +x or -x as the
parameters to pass to `chmod` based on whether the file is currently executable
or not. You can remove the +x/-x and change the parameter to anything you'd
like, such as 777, 2775, -wx, etc... The value given is simply given to the
system's chmod command.