Drill provides the script submit_plan to submit a logical or physical plan for execution. It was used often early in Drill's history, but is seldom used now. It's primary use is when testing, to submit a plan received from EXPLAIN PLAN.
The 1.8 release of Drill revised the launch scripts. That revision proposed dropping submit_plan from the released distribution. (DRILL-4752). In the end, we left the script in the distribution, but it was not tested.
To make the script work, it needs a six-character tweak to reflect the changes made in other scripts.