使用sleep命令.
原文链接：https://www.f2er.com/bash/387017.html例：
sleep .5 # Waits 0.5 second. sleep 5 # Waits 5 seconds. sleep 5s # Waits 5 seconds. sleep 5m # Waits 5 minutes. sleep 5h # Waits 5 hours. sleep 5d # Waits 5 days.
