Showing external command output only if not empty

Question

Is it possible to silently run an external command, but show the output on the prompt only if there was any?

Answer 1

If by external command you do mean shell commands then you can try using system function :h system():

No output (on Windows)

let s:output = system("title")
if s:output != ''
    echom s:output
endif

Output

let s:output = system("date")
if s:output != ''
    echom s:output
endif