How to pipe *characters* to cmd ( `:!` ) [duplicate]

Question

It is possible to pipe visually selected lines (i.e. selected with uppercase V) using :, after which I can enter a command in vim's command line, e.g.:

:'<,'>!python -m base64 -d

I'd like to do the same for the selected character range (i.e. selected with lowercase v). Using : still creates a linewise range (:'<'>). Trying to manually provide a character range like this:

:`<,`>!python -m base64 -d

Still does not work; it outputs this:

E492: Not an editor command: `<`>!python -m base64 -d

The question: How can I pipe visually selected characters to a system (cmd) program?

Answer 1

You can define a function in your .vimrc:

    function! GetVisualSelection()
    let [lnum1, col1] = getpos("'<")[1:2]
    let [lnum2, col2] = getpos("'>")[1:2]
    let lines = getline(lnum1, lnum2)
    let lines[-1] = lines[-1][: col2 - (&selection == 'inclusive' ? 1 : 2)]
    let lines[0] = lines[0][col1 - 1:]
    return join(lines, "\\n")
endfunction

And then execute something like this: <C-u>exe "!echo \"" . GetVisualSelection() . "\" | python -m base64 -d"

To give credits I took function from this SO answer, only change is last line to include double backslash to make it work in shell.

Answer 2

If someone looks for an answer, here is the one from Replace selection with output of external command

• c to put the visually selected text in the default ("") register
• Ctrl+r to execute a Vim command
• = to use the execute register
• system('whatever command', @") to pass the default register (@") to the system command
• Enter to execute the command
• Esc to return to the normal mode

This can be remapped to a shortcut

vnoremap <silent> <leader>btoa c<c-r>=system('base64 --decode --wrap=0', @")<cr><esc>