Switch to SpeakEasy.net DSL

The Modular Manual Browser

Home Page
Manual: (HP-UX-11.11)
Apropos / Subsearch:
optional field

 nice(1)							     nice(1)

      nice - run a command at nondefault priority

      nice [-priority_change] command [command_args]

      nice [-n priority_change] command [command_args]

      The nice command executes command at a nondefault CPU scheduling
      priority.	 (The name is derived from being "nice" to other system
      users by running large programs at lower priority.)

      The command-line arguments are as follows:

	   -n priority_change

	   priority_change The difference between the system nice value
			   (relative priority) of the current (or parent)
			   process and the actual system nice value at which
			   command is to run.

			   An unsigned value increases the system nice value
			   for command, causing it to run at lower priority.

			   A negative value requires superuser privileges,
			   and assigns a lower system nice value (higher
			   priority) to command.  If the current process is
			   not privileged, the value is silently treated as
			   if it were 0.

			   If the value of priority_change would result in a
			   system nice value outside the range 0 through 39,
			   the corresponding limit value of 0 or 39 is used

			   Note that a positive priority_change (lower
			   priority) has a single - option character before
			   the numeric value; a negative (higher priority)
			   priority_change has two: the option character
			   followed by the minus sign (--).  If -
			   priority_change is not specified, it defaults to

	   command	   A program, HP-UX command, user shell script, etc.
			   to be executed at the nondefault priority.
			   command can be run as a foreground or background

 Hewlett-Packard Company	    - 1 -   HP-UX Release 11i: November 2000

 nice(1)							     nice(1)

			   If command is run as a background process, any
			   nice priority_change made by the shell (ksh
			   executes all background processes via nice -4) is
			   in addition to that specified in the nice command

	   command_args	   Any arguments recognized by command.

    Process Priorities
      All processes have an associated system nice value which is used to
      compute the instantaneous-priority of the process when it is scheduled
      to run.  Normally, all processes inherit the system nice value of
      their parent process when they are spawned.  The shell (sh, csh, ksh,
      etc.) can create a child process with a different priority from the
      current shell process by spawning the child process via the nice
      command.	If the priority_change value is unsigned (positive), the
      child process is nicer (lower in priority) relative to the parent.  If
      the priority_change value is negative, the child process runs at a
      higher priority with a greater share of available system resources.
      To spawn a higher priority child process, the parent process must be
      owned by a user who has the appropriate privileges.

      At boot-up, the system starts the init process at a system nice value
      of 20 (system default).  On most systems, all processes (down to the
      login shells) inherit this priority.  Starting from their individual
      login shell processes, users can alter the system nice value of
      descendent processes to as much as 39, or, with appropriate
      privileges, as little as 0.  A system nice value of 0 establishes an
      extremely high priority, whereas a value of 39 indicates a very low

      Ordinary users can only increase the system nice value of any child
      process relative to the current process; i.e., priority_change must be
      a positive (unsigned) value, resulting in a lower priority.  To start
      a child process at a lower system nice value (higher priority) than
      the current process, the user must have the appropriate privileges,
      regardless of the relative nice-priority value desired.

      For example, using the command

	   nice ksh

      from a login shell whose current nice value is 20 spawns a subshell
      with a system nice value of 30.  Attempting to use

	   nice --2 ksh

      from the new shell to spawn another subshell whose system nice value
      would be 28, is rejected (unless the user has appropriate privileges),
      even though the resulting system nice value would be less than the
      priority of the original login shell process.

 Hewlett-Packard Company	    - 2 -   HP-UX Release 11i: November 2000

 nice(1)							     nice(1)

      The system nice value for current processes is listed under the NI
      column produced by the ps -l command (see ps(1)).

    Background Processes
      Foreground processes are run at same system nice value as the parent
      shell.  Background processes spawned by ksh run at the equivalent of a
      nice -4 by default.  If a background process is started via nice from
      ksh, any priority_change specified in the nice command is added to
      default nice -4.	Thus the command

	   nice 12 command &&amp&amp&

      runs at a system nice value of 36 if executed from ksh.

    Environment Variables
      LC_MESSAGES determines the language in which messages are displayed.

      If LC_MESSAGES is not specified in the environment or is set to the
      empty string, the value of LANG is used as a default for each
      unspecified or empty variable.  If LANG is not specified or is set to
      the empty string, a default of "C" (see lang(5)) is used instead of

      If any internationalization variable contains an invalid setting, nice
      behaves as if all internationalization variables are set to "C".	See

    International Code Set Support
      Single- and multi-byte character code sets are supported.

      nice returns the value returned by command.

      The following examples assume the current process is running with a
      system nice value of 20 and nice is executed from the Korn shell (see

      Run a program named prog in the current directory at the default
      priority_change of 10 (system nice value of 30):

	   nice ./prog prog_args

      Run the same program in the background using a system nice value of 36
      (priority_change=12 plus 4 for the Korn shell):

	   nice -12 ./prog prog_args &&amp&amp&

      As a user with appropriate privileges, run prog as a foreground
      process with a system nice value of 6:

 Hewlett-Packard Company	    - 3 -   HP-UX Release 11i: November 2000

 nice(1)							     nice(1)

	   nice --14 ./prog prog_args

      The C shell, csh, has a built-in nice command with different syntax.
      See csh(1) for details.

      csh(1), ksh(1), nohup(1), sh-bourne(1), sh-posix(1), sh(1),
      renice(1M), nice(2).

      nice: SVID2, SVID3, XPG4

 Hewlett-Packard Company	    - 4 -   HP-UX Release 11i: November 2000