Written by David Anderson on June 5, 2024 What is PID 0? I get nerd-sniped a lot. People offhandedly ask something innocent, and I lose the next several hours (or in this case, days) comprehensively figuring out the answer. Usually this ends up in a rant thread on mastodon or in some private chat group or other. But for once I have the energy to write one up for the blog. Today’s innocent question: Is there a reason UIDs start at 0 but PIDs start at 1? The very short version: Unix PIDs do start ...