Can I run fossilize manually?

Fossilize can take a bit of time when I want to start a game.
Is there a way I can stick a call to fossilize into a cron job and have it run in the background regularly?
I tried the naive approach of copying the call from ps, resulting in the following:

~/.local/share/Steam/ubuntu12_64/fossilize_replay \
  ~/.local/share/Steam/steamapps/shadercache/570/fozpipelinesv5/steamapp_pipeline_cache.foz \
  ~/.local/share/Steam/steamapps/shadercache/570/fozpipelinesv5/steam_pipeline_cache.foz \
  --on-disk-validation-whitelist ~/.local/share/Steam/steamapps/shadercache/570/fozpipelinesv5/steam_pipeline_cache_whitelist \
  --replayer-cache ~/.local/share/Steam/steamapps/shadercache/570/fozpipelinesv5/replay_cache \
  --master-process --quiet-slave --shmem-fd 132 --control-fd 145 --spirv-val --num-threads 3 \
  --device-index 0 --timeout-seconds 10 --implicit-whitelist 0
Fossilize INFO: Attempting to map shmem block.
Fossilize INFO: Using control FD as sentinel.
Fossilize ERROR: Failed to add control_fd to epoll.

Is the file descriptor created outside of fossilize? If so can I manually do it?

Start with the fossilize_replay invocation and the --shmem-fd, --control-fd, --master-process, and --quiet-slave options shown in the report. Determine whether this invocation is supported outside Steam and document the required setup, or clearly state that manual cron execution is not supported.