Write buffer list to file

Question

I would like to have a file that contains all files that I opened with vim in the past. I know that there is the viminfo file but I want to have just a file with the filenames.

For this I would like to write the list of open buffers with autocmd VimLeave to a file.

I tried :ls | w >> test.txt but this does not work correctly.

Answer 1

You can have all buffer names that haven't been unloaded (or wiped out?) with:

let files = filter(map(range(1,bufnr('$')), 'bufname(v:val)'), '!empty(v:val)')

You can save it with

call writefile(files, '/path/to/filename.txt')

Answer 2

Try using redir command (:h redir)

For example:

func! MyRedir() abort
    redir! > ~/test.txt
    :ls
    redir END
endfunc

augroup save_files | au!
    au VimLeave * call MyRedir()
augroup end

Answer 3

I took Luc Hermitte's helpful answer and improved it somewhat.

1. It was returning unlisted (previously deleted) buffers, which isn't what I wanted. It now filters on buflisted(v:val), rather than on !empty(v:val).
2. I've added two commands:
   • Lssave: saves the unsorted buffer list as-is
   • LSsave: saves a sorted version of the buffer list
3. mkdir the output file's path, in case it doesn't already exist.

function s:bufferList()
    let l:bufferRange = range(1,bufnr('$'))
    let l:bufferList = map(l:bufferRange, 'bufname(v:val)')
    let l:bufferListListed = filter(l:bufferList, 'buflisted(v:val)')
    return l:bufferListListed
endfunction

command Lssave
    \ let s:bufferList = s:bufferList() |
    \ call mkdir("/path/to", "p", 0740) |
    \ call writefile(s:bufferList, "/path/to/filename.txt")

command LSsave
    \ let s:bufferList = s:bufferList() |
    \ let s:bufferListSorted = sort(s:bufferList) |
    \ call mkdir("/path/to", "p", 0740) |
    \ call writefile(s:bufferListSorted, "/path/to/filename.txt")