Section (1) nice

Linux manual pages Section 1  


nice — run a program with modified scheduling priority


nice [OPTION] [ COMMAND [ARG...] ]


Run COMMAND with an adjusted niceness, which affects process scheduling. With no COMMAND, print the current niceness. Niceness values range from −20 (most favorable to the process) to 19 (least favorable to the process).

Mandatory arguments to long options are mandatory for short options too.

−n, −−adjustment=N/

add integer N to the niceness (default 10)


display this help and exit


output version information and exit

[Note] Note

Your shell may have its own version of nice, which usually supersedes the version described here. Please refer to your shell_zsingle_quotesz_s documentation for details about the options it supports.


Written by David MacKenzie.


GNU coreutils online help: <>

Report any translation bugs to <>


nice(2), renice(1)

Full documentation <>

or available locally via: info _zsingle_quotesz_(coreutils) nice invocation_zsingle_quotesz_


Copyright © 2019 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <>.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

Section (2) nice

Linux manual pages Section 2  


nice — change process priority


#include <unistd.h>
int nice( int inc);
[Note] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_XOPEN_SOURCE || /* Since glibc 2.19:
*/ _DEFAULT_SOURCE || /* Glibc versions <= 2.19:


nice() adds inc to the nice value for the calling thread. (A higher nice value means a low priority.)

The range of the nice value is +19 (low priority) to −20 (high priority). Attempts to set a nice value outside the range are clamped to the range.

Traditionally, only a privileged process could lower the nice value (i.e., set a higher priority). However, since Linux 2.6.12, an unprivileged process can decrease the nice value of a target process that has a suitable RLIMIT_NICE soft limit; see getrlimit(2) for details.


On success, the new nice value is returned (but see NOTES below). On error, −1 is returned, and errno is set appropriately.

A successful call can legitimately return −1. To detect an error, set errno to 0 before the call, and check whether it is nonzero after nice() returns −1.



The calling process attempted to increase its priority by supplying a negative inc but has insufficient privileges. Under Linux, the CAP_SYS_NICE capability is required. (But see the discussion of the RLIMIT_NICE resource limit in setrlimit(2).)


POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. However, the raw system call and (g)libc (earlier than glibc 2.2.4) return value is nonstandard, see below.


For further details on the nice value, see sched(7).

[Note] Note

the addition of the autogroup feature in Linux 2.6.38 means that the nice value no longer has its traditional effect in many circumstances. For details, see sched(7).

C library/kernel differences

POSIX.1 specifies that nice() should return the new nice value. However, the raw Linux system call returns 0 on success. Likewise, the nice() wrapper function provided in glibc 2.2.3 and earlier returns 0 on success.

Since glibc 2.2.4, the nice() wrapper function provided by glibc provides conformance to POSIX.1 by calling getpriority(2) to obtain the new nice value, which is then returned to the caller.


nice(1), renice(1), fork(2), getpriority(2), getrlimit(2), setpriority(2), capabilities(7), sched(7)


This page is part of release 4.16 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at−pages/.

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