Ctrl+T shows you what your terminal is doing
$ sleep 1 && sleep 1 && sleep 1
load: 1.31 cmd: sleep 60813 waiting 0.00u 0.00s
load: 1.31 cmd: sleep 60814 waiting 0.00u 0.00s
load: 1.31 cmd: sleep 60815 waiting 0.00u 0.00s
Useful if a script is stuck, shelling out, or you're curious why your prompt is taking so long to load.
from @aaronfeng