renice(1p) — Linux manual page


RENICE(1P)              POSIX Programmer's Manual             RENICE(1P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The
       Linux implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior),
       or the interface may not be implemented on Linux.

NAME         top

       renice — set nice values of running processes

SYNOPSIS         top

       renice [-g|-p|-u] -n increment ID...

DESCRIPTION         top

       The renice utility shall request that the nice values (see the
       Base Definitions volume of POSIX.1‐2017, Section 3.244, Nice
       Value) of one or more running processes be changed. By default,
       the applicable processes are specified by their process IDs. When
       a process group is specified (see -g), the request shall apply to
       all processes in the process group.

       The nice value shall be bounded in an implementation-defined
       manner.  If the requested increment would raise or lower the nice
       value of the executed utility beyond implementation-defined
       limits, then the limit whose value was exceeded shall be used.

       When a user is reniced, the request applies to all processes
       whose saved set-user-ID matches the user ID corresponding to the

       Regardless of which options are supplied or any other factor,
       renice shall not alter the nice values of any process unless the
       user requesting such a change has appropriate privileges to do so
       for the specified process. If the user lacks appropriate
       privileges to perform the requested action, the utility shall
       return an error status.

       The saved set-user-ID of the user's process shall be checked
       instead of its effective user ID when renice attempts to
       determine the user ID of the process in order to determine
       whether the user has appropriate privileges.

OPTIONS         top

       The renice utility shall conform to the Base Definitions volume
       of POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines, except
       for Guideline 9.

       The following options shall be supported:

       -g        Interpret the following operands as unsigned decimal
                 integer process group IDs.

       -n increment
                 Specify how the nice value of the specified process or
                 processes is to be adjusted. The increment option-
                 argument is a positive or negative decimal integer that
                 shall be used to modify the nice value of the specified
                 process or processes.

                 Positive increment values shall cause a lower nice
                 value. Negative increment values may require
                 appropriate privileges and shall cause a higher nice

       -p        Interpret the following operands as unsigned decimal
                 integer process IDs. The -p option is the default if no
                 options are specified.

       -u        Interpret the following operands as users. If a user
                 exists with a user name equal to the operand, then the
                 user ID of that user is used in further processing.
                 Otherwise, if the operand represents an unsigned
                 decimal integer, it shall be used as the numeric user
                 ID of the user.

OPERANDS         top

       The following operands shall be supported:

       ID        A process ID, process group ID, or user name/user ID,
                 depending on the option selected.

STDIN         top

       Not used.

INPUT FILES         top



       The following environment variables shall affect the execution of

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base
                 Definitions volume of POSIX.1‐2017, Section 8.2,
                 Internationalization Variables for the precedence of
                 internationalization variables used to determine the
                 values of locale categories.)

       LC_ALL    If set to a non-empty string value, override the values
                 of all the other internationalization variables.

       LC_CTYPE  Determine the locale for the interpretation of
                 sequences of bytes of text data as characters (for
                 example, single-byte as opposed to multi-byte
                 characters in arguments).

                 Determine the locale that should be used to affect the
                 format and contents of diagnostic messages written to
                 standard error.

       NLSPATH   Determine the location of message catalogs for the
                 processing of LC_MESSAGES.



STDOUT         top

       Not used.

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top




EXIT STATUS         top

       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.



       The following sections are informative.



EXAMPLES         top

        1. Adjust the nice value so that process IDs 987 and 32 would
           have a lower nice value:

               renice -n 5 -p 987 32

        2. Adjust the nice value so that group IDs 324 and 76 would have
           a higher nice value, if the user has appropriate privileges
           to do so:

               renice -n -4 -g 324 76

        3. Adjust the nice value so that numeric user ID 8 and user sas
           would have a lower nice value:

               renice -n 4 -u 8 sas

       Useful nice value increments on historical systems include 19 or
       20 (the affected processes run only when nothing else in the
       system attempts to run) and any negative number (to make
       processes run faster).

RATIONALE         top

       The gid, pid, and user specifications do not fit either the
       definition of operand or option-argument. However, for clarity,
       they have been included in the OPTIONS section, rather than the
       OPERANDS section.

       The definition of nice value is not intended to suggest that all
       processes in a system have priorities that are comparable.
       Scheduling policy extensions such as the realtime priorities in
       the System Interfaces volume of POSIX.1‐2017 make the notion of a
       single underlying priority for all scheduling policies
       problematic. Some implementations may implement the nice-related
       features to affect all processes on the system, others to affect
       just the general time-sharing activities implied by this volume
       of POSIX.1‐2017, and others may have no effect at all. Because of
       the use of ``implementation-defined'' in nice and renice, a wide
       range of implementation strategies are possible.

       Originally, this utility was written in the historical manner,
       using the term ``nice value''. This was always a point of concern
       with users because it was never intuitively obvious what this
       meant. With a newer version of renice, which used the term
       ``system scheduling priority'', it was hoped that novice users
       could better understand what this utility was meant to do. Also,
       it would be easier to document what the utility was meant to do.
       Unfortunately, the addition of the POSIX realtime scheduling
       capabilities introduced the concepts of process and thread
       scheduling priorities that were totally unaffected by the
       nice/renice utilities or the nice()/setpriority() functions.
       Continuing to use the term ``system scheduling priority'' would
       have incorrectly suggested that these utilities and functions
       were indeed affecting these realtime priorities. It was decided
       to revert to the historical term ``nice value'' to reference this
       unrelated process attribute.

       Although this utility has use by system administrators (and in
       fact appears in the system administration portion of the BSD
       documentation), the standard developers considered that it was
       very useful for individual end users to control their own

       Earlier versions of this standard allowed the following forms in
       the SYNOPSIS:

           renice nice_value[-p] pid...[-g gid...][-p pid...][-u user...]
           renice nice_value -g gid...[-g gid...]-p pid...][-u user...]
           renice nice_value -u user...[-g gid...]-p pid...][-u user...]

       These forms are no longer specified by POSIX.1‐2008 but may be
       present in some implementations.



SEE ALSO         top


       The Base Definitions volume of POSIX.1‐2017, Section 3.244, Nice
       Value, Chapter 8, Environment Variables, Section 12.2, Utility
       Syntax Guidelines

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  In the event of any
       discrepancy between this version and the original IEEE and The
       Open Group Standard, the original IEEE and The Open Group
       Standard is the referee document. The original Standard can be
       obtained online at .

       Any typographical or formatting errors that appear in this page
       are most likely to have been introduced during the conversion of
       the source files to man page format. To report such errors, see .

IEEE/The Open Group               2017                        RENICE(1P)

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