Task spooler is a Unix batch system where the tasks spooled run one after the other. Each user in each system has his own job queue. The tasks are run in the correct context (that of enqueue) from any shell/process, and its output/results can be easily watched. It is very useful when you know that your commands depend on a lot of RAM, a lot of disk use, give a lot of output, or for whatever reason it's better not to run them at the same time.