248 lines
5.8 KiB
HTML
248 lines
5.8 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of CHRT</TITLE>
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</HEAD><BODY>
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<H1>CHRT</H1>
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Section: User Commands (1)<BR>Updated: January 2016<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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chrt - manipulate the real-time attributes of a process
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>chrt</B>
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[options]
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<I>priority command </I>[<I>argument</I>...]
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<BR>
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<B>chrt</B>
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[options]
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<B>-p</B>
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[<I>priority</I>] <I>pid</I>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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<P>
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<B>chrt</B>
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sets or retrieves the real-time scheduling attributes of an existing <I>pid</I>,
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or runs <I>command</I> with the given attributes.
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<P>
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<A NAME="lbAE"> </A>
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<H2>POLICIES</H2>
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<DL COMPACT>
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<DT id="1"><B>-o</B>, <B>--other</B><DD>
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Set scheduling policy to
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<B>SCHED_OTHER</B>.
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This is the default Linux scheduling policy.
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<DT id="2"><B>-f</B>, <B>--fifo</B><DD>
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Set scheduling policy to <B>SCHED_FIFO</B>.
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<DT id="3"><B>-r</B>, <B>--rr</B><DD>
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Set scheduling policy to
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<B>SCHED_RR</B>.
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When no policy is defined, the
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<B>SCHED_RR</B>
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is used as the default.
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<DT id="4"><B>-b</B>, <B>--batch</B><DD>
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Set scheduling policy to
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<B>SCHED_BATCH</B>
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(Linux-specific, supported since 2.6.16). The priority argument has to be set to zero.
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<DT id="5"><B>-i</B>, <B>--idle</B><DD>
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Set scheduling policy to
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<B>SCHED_IDLE</B>
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(Linux-specific, supported since 2.6.23). The priority argument has to be set to zero.
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<DT id="6"><B>-d</B>, <B>--deadline</B>
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<DD>
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Set scheduling policy to
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<B>SCHED_DEADLINE</B>
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(Linux-specific, supported since 3.14). The priority argument has to be set to zero.
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See also <B>--sched-runtime</B>, <B>--sched-deadline</B> and
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<B>--sched-period</B>. The relation between the options required by the kernel is
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runtime <= deadline <= period.
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<B>chrt</B>
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copies <I>period</I> to <I>deadline</I> if <B>--sched-deadline</B> is not specified and
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<I>deadline</I> to <I>runtime</I> if <B>--sched-runtime</B> is not specified.
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It means that at least <B>--sched-period</B> has to be specified. See
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<B><A HREF="/cgi-bin/man/man2html?7+sched">sched</A></B>(7)
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for more details.
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<P>
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</DL>
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<A NAME="lbAF"> </A>
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<H2>SCHEDULING OPTIONS</H2>
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<DL COMPACT>
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<DT id="7"><B>-T</B>, <B>--sched-runtime</B> <I>nanoseconds</I><DD>
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Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
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<DT id="8"><B>-P</B>, <B>--sched-period</B> <I>nanoseconds</I><DD>
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Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
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<DT id="9"><B>-D</B>, <B>--sched-deadline</B> <I>nanoseconds</I><DD>
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Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
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<DT id="10"><B>-R</B>, <B>--reset-on-fork</B><DD>
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Add
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<B>SCHED_RESET_ON_FORK</B>
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flag to the
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<B>SCHED_FIFO</B>
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or
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<B>SCHED_RR</B>
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scheduling policy (Linux-specific, supported since 2.6.31).
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<P>
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</DL>
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<A NAME="lbAG"> </A>
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<H2>OPTIONS</H2>
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<DL COMPACT>
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<DT id="11"><B>-a</B>, <B>--all-tasks</B>
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<DD>
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Set or retrieve the scheduling attributes of all the tasks (threads) for a
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given PID.
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<DT id="12"><B>-m</B>, <B>--max</B>
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<DD>
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Show minimum and maximum valid priorities, then exit.
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<DT id="13"><B>-p</B>, <B>--pid</B>
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<DD>
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Operate on an existing PID and do not launch a new task.
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<DT id="14"><B>-v</B>, <B>--verbose</B>
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<DD>
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Show status information.
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<DT id="15"><B>-V</B>, <B>--version</B>
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<DD>
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Display version information and exit.
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<DT id="16"><B>-h</B>, <B>--help</B>
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<DD>
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Display help text and exit.
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</DL>
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<A NAME="lbAH"> </A>
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<H2>USAGE</H2>
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<DL COMPACT>
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<DT id="17">The default behavior is to run a new command:<DD>
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<B>chrt</B>
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<I>priority</I>
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<I>command </I>[<I>arguments</I>]
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<DT id="18">You can also retrieve the real-time attributes of an existing task:<DD>
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<B>chrt -p</B>
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<I>pid</I>
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<DT id="19">Or set them:<DD>
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<B>chrt -r -p</B>
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<I>priority pid</I>
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</DL>
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<A NAME="lbAI"> </A>
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<H2>PERMISSIONS</H2>
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A user must possess
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<B>CAP_SYS_NICE</B>
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to change the scheduling attributes of a process. Any user can retrieve the
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scheduling information.
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<P>
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<A NAME="lbAJ"> </A>
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<H2>NOTES</H2>
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Only
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<B>SCHED_FIFO</B>,
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<B>SCHED_OTHER</B>
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and
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<B>SCHED_RR</B>
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are part of POSIX 1003.1b Process Scheduling. The other scheduling attributes
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may be ignored on some systems.
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<P>
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Linux' default scheduling policy is
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<B>SCHED_OTHER</B>.
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<A NAME="lbAK"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?1+nice">nice</A></B>(1),
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<B><A HREF="/cgi-bin/man/man2html?1+renice">renice</A></B>(1),
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<B><A HREF="/cgi-bin/man/man2html?1+taskset">taskset</A></B>(1),
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<B><A HREF="/cgi-bin/man/man2html?7+sched">sched</A></B>(7)
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<P>
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See
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<B><A HREF="/cgi-bin/man/man2html?2+sched_setscheduler">sched_setscheduler</A></B>(2)
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for a description of the Linux scheduling scheme.
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<A NAME="lbAL"> </A>
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<H2>AUTHORS</H2>
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Robert Love
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<BR>
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Karel Zak
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<A NAME="lbAM"> </A>
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<H2>AVAILABILITY</H2>
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The chrt command is part of the util-linux package and is available from
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<A HREF="https://www.kernel.org/pub/linux/utils/util-linux/.">https://www.kernel.org/pub/linux/utils/util-linux/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="20"><A HREF="#lbAB">NAME</A><DD>
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<DT id="21"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="22"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="23"><A HREF="#lbAE">POLICIES</A><DD>
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<DT id="24"><A HREF="#lbAF">SCHEDULING OPTIONS</A><DD>
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<DT id="25"><A HREF="#lbAG">OPTIONS</A><DD>
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<DT id="26"><A HREF="#lbAH">USAGE</A><DD>
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<DT id="27"><A HREF="#lbAI">PERMISSIONS</A><DD>
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<DT id="28"><A HREF="#lbAJ">NOTES</A><DD>
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<DT id="29"><A HREF="#lbAK">SEE ALSO</A><DD>
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<DT id="30"><A HREF="#lbAL">AUTHORS</A><DD>
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<DT id="31"><A HREF="#lbAM">AVAILABILITY</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:09 GMT, March 31, 2021
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