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I'd like to view output of big commands slowed down, like a slideshow with e.g. automatic, 500ms delay between each scroll. What is the simplest way to achieve this?

Blazej Wieliczko
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3 Answers3

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A simple solution using bash:

function scroll
{
    while read -r ; do echo "$REPLY" ; sleep ${1:-0.5} ; done
}

Usage

long_command | scroll [delay]

delay is optional and defaults to 0.5.

Exit with Ctrl+C

cYrus
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    I don't know why my edit get rejected, but be warned that `echo /** ` in your output of long_command (e.g. `cat` a file) will stuck and flood your terminal session if you don't put double quotes on `"$REPLY"`. – 林果皞 Mar 21 '18 at 20:51
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    @林果皞 approved and removed the warning, thanks. I should have added the quotes in the first place. – cYrus Mar 23 '18 at 13:49
  • ... I added the warning just because system doesn't allow edit only 2 characters. – 林果皞 Mar 23 '18 at 13:57
4

If you can live with 1s resolution, you could do tail -n +0 -f -s <seconds>.

Nicole Hamilton
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    The output from `long_command` is possibly generated in less than a second so there's no point in polling for its completeness every `` and indeed doesn't work for me. – cYrus Sep 10 '12 at 22:25
2

You could use vim with an appropriate mapping to achieve this:

vim -c 'map <S-f20> L:redraw<cr>:sleep 500m<cr><C-d><S-f20>' -c 'execute "normal \<S-f20>"' -

Ctrl-d scrolls half a page at a time, replace with 10j to scroll 10 lines at a time.

Thor
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