Section (1) nice
nice — run a program with modified scheduling priority
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.
add integer N to the niceness (default 10)
display this help and exit
output version information and exit
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.
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
Full documentation <https://www.gnu.org/software/coreutils/nice>
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 <https://gnu.org/licenses/gpl.html>.
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
nice — change process priority
inc to the nice value for the
calling thread. (A higher nice value means a low
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
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
incbut has insufficient privileges. Under Linux, the
CAP_SYS_NICEcapability is required. (But see the discussion of the
RLIMIT_NICEresource 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).
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.
function provided in glibc 2.2.3 and earlier returns 0 on
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
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Copyright (c) 1992 Drew Eckhardt <drewcs.colorado.edu>, March 28, 1992
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Modified by Michael Haardt <michaelmoria.de>
Modified 1993-07-24 by Rik Faith <faithcs.unc.edu>
Modified 1996-11-04 by Eric S. Raymond <esrthyrsus.com>
Modified 2001-06-04 by aeb
Modified 2004-05-27 by Michael Kerrisk <mtk.manpagesgmail.com>