Answer by Ralf for How to execute selected lines in bash and print the output in the next line?

I would propose the following:

nnoremap _X  :put =system(getline('.'))<cr>vnoremap _X  :<C-U>'>put =system(join(getline('''<','''>'),\"\n\").\"\n\")<cr>

The first mapping is to execute a single line. Just put the cursor in the line and hit _X. This takes the current line (getline(".")), executes it (system(...)) and puts the returned result below the current line.

The visual mode mapping works similar, but

• `getline('''<', '''>') fetches the list of selected lines
• join(..., "\n")."\n" joins the list into one string
• finally put puts the result below the last selected line, due to the leading `'>'