Changes the priority of a command
nice [option] [command line]
The nice utility reports the priority of the shell or alters the priority of a command line. An ordinary user can decrease the priority of a command. Only Superuser can increase the priority of a command. The TC Shell has a nice builtin that has a different syntax. Refer to “Notes.”
The command line is the command line you want to execute at a different priority. Without any options or arguments, nice reports the priority of the shell running the nice command.
Without an option, nice defaults to an adjustment of 10, lowering the priority of the command by 10, typically from 0 to 10. (As you raise the priority value, the command is run at a lower priority.) ...