caffeinate -u -d

My MacBook Pro running Catalina has been crashing when:

1. attached to an external monitor (an LG UltraFine 5K Display),
2. in clamshell mode, and
3. it goes to sleep

This looks like a known bug according to forum posts like this and this.

My workaround for now has been:

1. manually put the computer to sleep when I step away or
2. not use the monitor or
3. when running a long-running process and I want to step away, running caffeinate in a shell to prevent idle sleep:

caffeinate -u -d