These docs are under active development.
Peios Learn
On this page
reference 1 min read

nice

nice runs a command at an adjusted scheduling priority — making it more, or less, willing to give the processor up to other work.

nice [options] [command [arg]...]

$ nice -n 15 big-batch-job

With no command, nice prints the current niceness.

Niceness

A process has a niceness — a number from -20 to 19:

  • A high niceness (toward 19) means the process is "nicer" to others — it yields the processor readily. Good for background work that should not get in the way.
  • A low niceness (toward -20) means the process is favoured — it gets the processor more often.

By default nice adds 10 to the niceness, making the command run in the background more gracefully.

Option Effect
-n, --adjustment=N Add N to the niceness instead of 10. N may be negative.

Raising a command's niceness — running it lower priority — is always allowed. Lowering the niceness, to claim a higher priority than normal, is a privileged request and may be refused; when it is, nice warns and runs the command at the priority it was permitted.

Exit status

When nice runs a command, it exits with that command's status. The exception is a failure in nice itself:

Code Meaning
(command's own) The command ran; this is its exit status.
0 No command was given; the niceness was printed.
125 nice itself failed — for example, a bad adjustment value.
126 The command was found but could not be run.
127 The command was not found.

See also