How can save help document to a file?

Question

In vim :h UltiSnips-python in ex-mode can display all info on python usage in UltiSnips. I want to save all the output as /tmp/vim.output.

:redir > /tmp/vim.output | :h UltiSnips-python   | redir END

It can't work,how can fix then?

Answer 1

:help command opens a text file and redir command can not do anything about it.

Vim's help is just a collection of txt files located in respected doc/ folders. You can either navigate there and do whatever needed with the file itself (copy to /tmp/vim.output) or you can use :w command to write help buffer contents to some other file: