mhoyeMar 17

Is there an elegant way, in the shell, to say “run this program until this other program is finished”?

I know I could run a thing, get a PID and then append a command with “&& kill pid” or something but that feels clunky.

Show threadwaffles 🇨🇦Mar 17

@mhoye isn’t that what the ‘wait’ cmd does?

Edit: oh I understand what you’re saying. That sounds more complicated and now I also want to know if there’s an existing solution.

Show threadmhoyeMar 17
@waffles I thought wait was “pause here until a process exits and then continue” but not “run foo until that process exits” without extra work.
Show threadGlyphMar 17
@mhoye @waffles the "until" in "run foo until" suggests a signal at the end though, which means you've got all the usual signal handling choices (HUP? INT? TERM? KILL? start with one and escalate?), so "$!" and kill and wait seems somewhat necessary
Show threadGlyphMar 17
@mhoye @waffles not to mention who wants what file descriptors. can you say anything else about the underlying problem?
Show threadmhoyeMar 17
@glyph @waffles Really, the underlying problem is that I have a program to run that's single threaded, offers no visible progress indicators and might take ages. All I want is "run [screensaver] until [job] finishes then pop up [alert]"
Show threadGlyphMar 17
@mhoye @waffles yeah I golfed it for a while but really can't come up with anything better than https://gist.github.com/glyph/a063c96615dbebc1d43109610407b433
firstsecond.sh

GitHub Gist: instantly share code, notes, and snippets.

Gist
Show threadmhoyeMar 17
@glyph @waffles that is very similar to where I ended up, too. Thanks for taking a look.
Show threadGlyph
@mhoye @waffles it was an interesting problem and definitely one I've faced before. real solution is of course your main thing should have a --progress option :). I'll follow up if ricocheting thoughts produce something better later
Mar 17 at 7:03pmWeb
Show threadsamir, a terminally deprecated methodMar 17

@glyph @mhoye @waffles This doesn’t solve the problem completely, but in case it’s useful: you might find pv helpful. It will render a progress bar and pipe a file into stdout, which you can then pipe to another process.

https://man7.org/linux/man-pages/man1/pv.1.html

pv(1) - Linux manual page

Show threadGlyphMar 17
@samir @mhoye @waffles I skipped over recommendations like this (and others, like zsh coproc) because I assumed if some file I/O were happening he would have said so, but perhaps useful for onlookers :)