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<h1 class="settitle" align="center">Ntp-wait User&rsquo;s Manual</h1>





<a name="Top"></a>
<div class="header">
<p>
Previous: <a href="dir.html#Top" accesskey="p" rel="prev">(dir)</a>, Up: <a href="dir.html#Top" accesskey="u" rel="up">(dir)</a> &nbsp; </p>
</div>
<h1 class="node-heading">Top</h1>

<p>This document describes the use of the NTP Project&rsquo;s <code>ntp-wait</code> program.
</p>
<p>If there are time-sensitive applications,
the proper sequence of events is to
run <code>ntpd -g</code> as early as possible,
then invoke all of the non-time-sensitive process,
run <code>ntp-wait</code> to block
until the system&rsquo;s time has stabilized and synchronized,
and only then start any applicaitons (like database servers) that require
accurate and stable time.
</p>
<p>This document applies to version 4.2.8p15 of <code>ntp-wait</code>.
</p>
<a name="SEC_Overview"></a>
<h2 class="shortcontents-heading">Short Table of Contents</h2>

<div class="shortcontents">
<li><a name="stoc-Invoking-ntp_002dwait" href="#toc-Invoking-ntp_002dwait">1 Invoking ntp-wait</a></li>

</div>


<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; ntp-wait Description:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Description
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-Invocation" accesskey="2">ntp-wait Invocation</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Invoking ntp-wait
</td></tr>
</table>

<hr>
<a name="ntp_002dwait-Invocation"></a>
<div class="header">
<p>
Up: <a href="#Top" accesskey="u" rel="up">Top</a> &nbsp; </p>
</div>
<a name="Invoking-ntp_002dwait"></a>
<h3 class="section">1 Invoking ntp-wait</h3>
<a name="index-ntp_002dwait"></a>
<a name="index-Wait-for-ntpd-to-stabilize-the-system-clock"></a>



<p><code>ntp-wait</code>
will send at most
<kbd>num-tries</kbd>
queries to
<code>ntpd(8)</code>,
sleeping for
<kbd>secs-between-tries</kbd>
after each status return that says
<code>ntpd(8)</code>
has not yet produced a synchronized and stable system clock.
</p>
<p><code>ntp-wait</code>
will do this quietly, unless the
<code>-v</code>
flag is provided.
This can be useful at boot time, to delay the boot sequence until after
<kbd>ntpd</kbd> <kbd>-g</kbd>
has set the time.
</p>
<p>This section was generated by <strong>AutoGen</strong>,
using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-wait</code> program.
</p>
<table class="menu" border="0" cellspacing="0">
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-usage" accesskey="1">ntp-wait usage</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">ntp-wait help/usage (<samp>--help</samp>)
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-tries" accesskey="2">ntp-wait tries</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">tries option (-n)
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-sleep" accesskey="3">ntp-wait sleep</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">sleep option (-s)
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-verbose" accesskey="4">ntp-wait verbose</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">verbose option (-v)
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-exit-status" accesskey="5">ntp-wait exit status</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">exit status
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-Authors" accesskey="6">ntp-wait Authors</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Authors
</td></tr>
<tr><td align="left" valign="top">&bull; <a href="#ntp_002dwait-Notes" accesskey="7">ntp-wait Notes</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Notes
</td></tr>
</table>

<hr>
<a name="ntp_002dwait-usage"></a>
<div class="header">
<p>
Next: <a href="#ntp_002dwait-tries" accesskey="n" rel="next">ntp-wait tries</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="ntp_002dwait-help_002fusage-_0028_002d_002dhelp_0029"></a>
<h4 class="subsection">1.1 ntp-wait help/usage (<samp>--help</samp>)</h4>
<a name="index-ntp_002dwait-help"></a>

<p>This is the automatically generated usage text for ntp-wait.
</p>
<p>The text printed is the same whether selected with the <code>help</code> option
(<samp>--help</samp>) or the <code>more-help</code> option (<samp>--more-help</samp>).  <code>more-help</code> will print
the usage text by passing it through a pager program.
<code>more-help</code> is disabled on platforms without a working
<code>fork(2)</code> function.  The <code>PAGER</code> environment variable is
used to select the program, defaulting to <samp>more</samp>.  Both will exit
with a status code of 0.
</p>
<div class="example">
<pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p15
USAGE: ntp-wait [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]... 

    -n, --tries=num              Number of times to check ntpd
    -s, --sleep=num              How long to sleep between tries
    -v, --verbose                Be verbose
    -?, --help                   Display usage information and exit
        --more-help              Pass the extended usage text through a pager

Options are specified by doubled hyphens and their name or by a single
hyphen and the flag character.
</pre></div>

<hr>
<a name="ntp_002dwait-tries"></a>
<div class="header">
<p>
Next: <a href="#ntp_002dwait-sleep" accesskey="n" rel="next">ntp-wait sleep</a>, Previous: <a href="#ntp_002dwait-usage" accesskey="p" rel="prev">ntp-wait usage</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="tries-option-_0028_002dn_0029"></a>
<h4 class="subsection">1.2 tries option (-n)</h4>
<a name="index-ntp_002dwait_002dtries"></a>

<p>This is the &ldquo;number of times to check ntpd&rdquo; option.
This option takes a number argument.
        The maximum number of times we will check <code>ntpd</code> to see if
        it has been able to synchronize and stabilize the system clock.
</p><hr>
<a name="ntp_002dwait-sleep"></a>
<div class="header">
<p>
Next: <a href="#ntp_002dwait-verbose" accesskey="n" rel="next">ntp-wait verbose</a>, Previous: <a href="#ntp_002dwait-tries" accesskey="p" rel="prev">ntp-wait tries</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="sleep-option-_0028_002ds_0029"></a>
<h4 class="subsection">1.3 sleep option (-s)</h4>
<a name="index-ntp_002dwait_002dsleep"></a>

<p>This is the &ldquo;how long to sleep between tries&rdquo; option.
This option takes a number argument <samp>secs-between-tries</samp>.
        We will sleep for <samp>secs-between-tries</samp> after each query
        of <code>ntpd</code> that returns &quot;the time is not yet stable&quot;.
</p><hr>
<a name="ntp_002dwait-verbose"></a>
<div class="header">
<p>
Next: <a href="#ntp_002dwait-exit-status" accesskey="n" rel="next">ntp-wait exit status</a>, Previous: <a href="#ntp_002dwait-sleep" accesskey="p" rel="prev">ntp-wait sleep</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="verbose-option-_0028_002dv_0029"></a>
<h4 class="subsection">1.4 verbose option (-v)</h4>
<a name="index-ntp_002dwait_002dverbose"></a>

<p>This is the &ldquo;be verbose&rdquo; option.
        By default, <code>ntp-wait</code> is silent.
        With this option, <code>ntp-wait</code> will provide status information.
</p><hr>
<a name="ntp_002dwait-exit-status"></a>
<div class="header">
<p>
Next: <a href="#ntp_002dwait-Authors" accesskey="n" rel="next">ntp-wait Authors</a>, Previous: <a href="#ntp_002dwait-verbose" accesskey="p" rel="prev">ntp-wait verbose</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="ntp_002dwait-exit-status-1"></a>
<h4 class="subsection">1.5 ntp-wait exit status</h4>

<p>One of the following exit values will be returned:
</p><dl compact="compact">
<dt>&lsquo;<samp>0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
<dd><p>Successful program execution.
</p></dd>
<dt>&lsquo;<samp>1 (EXIT_FAILURE)</samp>&rsquo;</dt>
<dd><p>The operation failed or the command syntax was not valid.
</p></dd>
</dl>
<hr>
<a name="ntp_002dwait-Authors"></a>
<div class="header">
<p>
Next: <a href="#ntp_002dwait-Notes" accesskey="n" rel="next">ntp-wait Notes</a>, Previous: <a href="#ntp_002dwait-exit-status" accesskey="p" rel="prev">ntp-wait exit status</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="ntp_002dwait-Authors-1"></a>
<h4 class="subsection">1.6 ntp-wait Authors</h4>
<hr>
<a name="ntp_002dwait-Notes"></a>
<div class="header">
<p>
Previous: <a href="#ntp_002dwait-Authors" accesskey="p" rel="prev">ntp-wait Authors</a>, Up: <a href="#ntp_002dwait-Invocation" accesskey="u" rel="up">ntp-wait Invocation</a> &nbsp; </p>
</div>
<a name="ntp_002dwait-Notes-1"></a>
<h4 class="subsection">1.7 ntp-wait Notes</h4>
<hr>



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