Macos – Open Macvim within terminal without opening a new window

The ConqueTerm Vim plugin provides GUI-based instances of Vim with a fairly robust terminal emulation. It requires Vim 7.0+ (7.3+ for Windows) compiled with +python or +python3; MacVim satisfies these requirements.

Here is a function and binding that re-implements the functionality of the normal-mode K command using ConqueTerm (you can put it in your .vimrc):

:function! ConqueMan()
    let cmd = &keywordprg . ' '
    if cmd ==# 'man ' || cmd ==# 'man -s '
        if v:count > 0
            let cmd .= v:count . ' '
        else
            let cmd = 'man '
        endif
    endif
    let cmd .= expand('<cword>')
    execute 'ConqueTermSplit' cmd
:endfunction
:map K :<C-U>call ConqueMan()<CR>
:ounmap K

$ mvim --remote-tab file3

MacVim first window is a Vim instance with --servername set to VIM. Each subsequent instance is named VIM1, VIM2 and so on. The command above opens a new tab in the first instance by default, it's the equivalent of:

$ mvim --servername VIM --remote-tab .profile

If you want to open a tab in a specific instance, check its name at the top of the window. Assuming it's VIM1, do:

$ mvim --servername VIM1 --remote-tab .profile