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List background jobs, grep their number - not process id - and then kill them
make, find and a lot of other programs can take a lot of time. And can do not. Supppose you write a long, complicated command and wonder if it will be done in 3 seconds or 20 minutes. Just add "R" (without quotes) suffix to it and you can do other things: zsh will inform you when you can see the results.
You can replace zenity with other X Window dialogs program.