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Vim's new :terminal feature is pretty neat, but when I run something like a rails server, I want to be able to clear logging output every now and then.

The usual methods in a non-vim term window don't seem to work, like <D-k> (Cmd-k clears scrollback in Terminal.app on macOS), etc.

I've tried <C-w>:Clear<CR>, but it seems to be for something different as well.

If I weren't running a rails server, I could just type clear in the terminal.

I glanced through :help :term, and I'm not seeing what I want jump out at me.

D. Ben Knoble
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Wumbo
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  • Isnt <C-l> the standard clear key? – D. Ben Knoble Nov 16 '18 at 20:43
  • C-l is redraw. C-l actually does look like it clears the term window in Vim, but inconveniently it does not work when you have a process like rails server running. It has to be implemented by vim itself, because obviously if I use the terminal's actual clear key, it will wipe the whole screen including vim (which of course comes back if I hit C-l to redraw).

    Perhaps this is just an edge case the new feature just hasn't addressed yet. Because it should be simple. You also can't <C-\><C-n> and delete the text, because modifiable is off and cannot be turned on for a running process.

     – Wumbo Nov 16 '18 at 23:15
  • Bizarre... if i do :term and then press <C-l> in my spawned shell it clears the term screen – D. Ben Knoble Nov 16 '18 at 23:24
  • Yes, but try that after starting a process that needs C-c to end. Or just do sleep 10000 and try to C-l before it is done. This is actually the case for a non-vim terminal as well. – Wumbo Nov 16 '18 at 23:27
  • Well sure, the term never gets the clear. Hmm. I see the issue now – D. Ben Knoble Nov 16 '18 at 23:29
  • It will actually clear after the process ends. It has to wait though, which super-k on mac terminal would not. Just looking for the equivalent in vim term. – Wumbo Nov 16 '18 at 23:32
  • One workaround might be set scbk=1 to make it forget the old lines, then set scbk=100000 to get back to normal operation. It doesn't actually clear the window though. – Amadan Sep 18 '19 at 04:30
  • @Amadan I think that one is for neovim ('scrollback'). → https://vi.stackexchange.com/questions/21260/how-to-clear-neovim-terminal-buffer For vim it's 'termwinscroll' / 'twsl' but it doesn't quite work. (still leave a screenful of lines) Neither does tput reset, printf '\ec', (← by the way this makes the cursor blinks for some weird reason, printf '\e[2 q' to reset) – – user202729 Jan 25 '22 at 07:51

4 Answers4

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Use https://github.com/kassio/neoterm.

It provides A better terminal support.

You can use the command :<terminal number>Tclear to clear the terminal. :Tclear for the last opened/active terminal (not sure which).

eyal karni
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I don't know how to clear the previous texts but if you have problem with scrolling back to the last command after executing it you can go to text mood by pressing ctrl + W N and set mark by pressing m <any key on the keyboard> press i to comeback to interactive mode and and execute your command and when you finished again go back to text mode by pressing ctrl + W N and go to the previously marked place by pressing ' <that key you have pressed before>.

princebillyGK
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Going through Vim's terminal.txt, I don't think you have a chance to clear the window.

It's because Vim doesn't do anything about <c-l>, just passing it as well as other typed keys to the running job, like bash or rails server. (when your focus is in the window)

The <c-w>:clear doesn't do the trick, either. The command is abbreviation of :clearjumps for newer Vim versions.

For normal terminal, like gnome-terminal or mac's terminal, it's the terminal dealing with your <c-l> or <cmd-l>, <cmd-k>. Vim's terminal looks not doing it.

However, I happened to try out a workaround. You can try it for your environment:

:tmap <c-l> <c-w>s<c-w>c

  • tmap is mapping specific for terminal job mode.
  • <c-w>s creates a new window, and when <c-w>c closes it and gets back, the terminal is cleared.
Charles Jie
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  • Sorry, but c-w s c-w c also does not work. You can try with sleep 10000. Text for processes in progress is not lost. There's probably situations where that is desirable. I agree, there are commands that vim is interpreting, and commands that the terminal app is interpreting. :clear and :Clear are different. vim terminal has some idea about breakpoints. I'm not entirely sure what it is about. – Wumbo Nov 17 '18 at 13:53
  • Let's check the version: I tested it with Vim 2.8.0 on ubuntu 18.04. However, I don't have gui on this server. I 'ssh' to the server and launch 'screen' to work with. Both sides are gnome-terminal.

    I don't understand why you test with "sleep 10000". It doesn't have anything on screen for your to CLEAR. (If you run it by ":term sleep 10000".)

    I test with ":term tail -f /var/log/syslog", which spit out log info from time to time. It works very well.

     – Charles Jie Nov 17 '18 at 16:47
  • sleep is just an example of a long running process for someone who isn't using rails server or similar. Start :term without an argument. type echo 'test'. type sleep 10000. tail gives output instantly, so it's not a good example. You don't have to remap <C-l> for tail, it would work already because it is finished quickly. – Wumbo Nov 17 '18 at 22:15
  • There is some misunderstanding. Tail with option '-f' (follow) will track a growing file and keep printing to the screen. It's a good way to simulate the so-called 'log' behavior of a server. You can either test with it directly via :term tail -f GROWING_FILE or run it in the bash called :term. – Charles Jie Nov 17 '18 at 23:22
  • In addition, tail -f will never come back until you press . It's better than sleep 10000 because it has output from time to time. – Charles Jie Nov 17 '18 at 23:34
  • I see, no I didn't realise that's what that option did. Your strategy still doesn't work. My version output is this: vim --version VIM - Vi IMproved 8.1 (2018 May 18, compiled Oct 3 2018 05:41:40) macOS version Included patches: 1-450 Compiled by Homebrew – Wumbo Nov 19 '18 at 19:21
0

put this in ~/.zshrc:

# I export nvimServer_4_TermAPI, a env-var defined by myself, in some other place...
cle(){
    clear
    nvim --server "$nvimServer_4_TermAPI" \
         --remote-expr   "Tapi_clear(0)"
}

put this in init.vim:

    func! Tapi_clear(buf) abort
        try
            let ori_scrollback = getbufvar('', '&scrollback')
            setl scrollback=1
            sleep 100m
            exe 'setl scrollback=' . ori_scrollback
        catch
            echom 'Tapi_clear有错'
        endtry
        return ''
    endf

Inspired by this in autoload/neoterm.vim of https://github.com/kassio/neoterm:

        if get(a:opts, 'force_clear', 0)
            let l:bufname = bufname(l:instance.buffer_id)
            let l:scrollback = getbufvar(l:bufname, '&scrollback')

        call setbufvar(l:bufname, '&amp;scrollback', 1)
        sleep 100m
        call setbufvar(l:bufname, '&amp;scrollback', l:scrollback)
    end

About shell command clear

https://unix.stackexchange.com/questions/410708/the-easiest-way-to-clear-scrollback-buffer-of-terminal-some-deeper-explanation/741099#741099

Good Pen
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