<html lang="en"> <head> <title>Ntp-wait User's Manual</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="Ntp-wait User's Manual"> <meta name="generator" content="makeinfo 4.7"> <link title="Top" rel="top" href="#Top"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family: serif; font-weight: normal; } --></style> </head> <body> <h1 class="settitle">Ntp-wait User's Manual</h1> <div class="node"> <p><hr> <a name="Top"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Description">ntp-wait Description</a>, Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>, Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> <br> </div> <p>This document describes the use of the NTP Project's <code>ntp-wait</code> program. <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's time has stabilized and synchronized, and only then start any applicaitons (like database servers) that require accurate and stable time. <p>This document applies to version 4.2.8p10 of <code>ntp-wait</code>. <div class="shortcontents"> <h2>Short Contents</h2> <ul> </ul> </div> <ul class="menu"> <li><a accesskey="1" href="#ntp_002dwait-Description">ntp-wait Description</a>: Description <li><a accesskey="2" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>: Invoking ntp-wait </ul> <div class="node"> <p><hr> <a name="ntp_002dwait-Invocation"></a> <br> </div> <h3 class="section">0.1 Invoking ntp-wait</h3> <p><a name="index-ntp_002dwait-1"></a><a name="index-Wait-for-ntpd-to-stabilize-the-system-clock-2"></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><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>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. <ul class="menu"> <li><a accesskey="1" href="#ntp_002dwait-usage">ntp-wait usage</a>: ntp-wait help/usage (<span class="option">--help</span>) <li><a accesskey="2" href="#ntp_002dwait-tries">ntp-wait tries</a>: tries option (-n) <li><a accesskey="3" href="#ntp_002dwait-sleep">ntp-wait sleep</a>: sleep option (-s) <li><a accesskey="4" href="#ntp_002dwait-verbose">ntp-wait verbose</a>: verbose option (-v) <li><a accesskey="5" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>: exit status <li><a accesskey="6" href="#ntp_002dwait-Authors">ntp-wait Authors</a>: Authors <li><a accesskey="7" href="#ntp_002dwait-Notes">ntp-wait Notes</a>: Notes </ul> <div class="node"> <p><hr> <a name="ntp_002dwait-usage"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-tries">ntp-wait tries</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.1 ntp-wait help/usage (<span class="option">--help</span>)</h4> <p><a name="index-ntp_002dwait-help-3"></a> This is the automatically generated usage text for ntp-wait. <p>The text printed is the same whether selected with the <code>help</code> option (<span class="option">--help</span>) or the <code>more-help</code> option (<span class="option">--more-help</span>). <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 <span class="file">more</span>. Both will exit with a status code of 0. <pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p10 USAGE: ntp-wait [ -<flag> [<val>] | --<name>[{=| }<val>] ]... -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 class="node"> <p><hr> <a name="ntp_002dwait-tries"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-sleep">ntp-wait sleep</a>, Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-usage">ntp-wait usage</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.2 tries option (-n)</h4> <p><a name="index-ntp_002dwait_002dtries-4"></a> This is the “number of times to check ntpd” 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. <div class="node"> <p><hr> <a name="ntp_002dwait-sleep"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-verbose">ntp-wait verbose</a>, Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-tries">ntp-wait tries</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.3 sleep option (-s)</h4> <p><a name="index-ntp_002dwait_002dsleep-5"></a> This is the “how long to sleep between tries” option. This option takes a number argument <span class="file">secs-between-tries</span>. We will sleep for <span class="file">secs-between-tries</span> after each query of <code>ntpd</code> that returns "the time is not yet stable". <div class="node"> <p><hr> <a name="ntp_002dwait-verbose"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>, Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-sleep">ntp-wait sleep</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.4 verbose option (-v)</h4> <p><a name="index-ntp_002dwait_002dverbose-6"></a> This is the “be verbose” option. By default, <code>ntp-wait</code> is silent. With this option, <code>ntp-wait</code> will provide status information. <div class="node"> <p><hr> <a name="ntp_002dwait-exit-status"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Authors">ntp-wait Authors</a>, Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-verbose">ntp-wait verbose</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.5 ntp-wait exit status</h4> <p>One of the following exit values will be returned: <dl> <dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution. <br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid. </dl> <div class="node"> <p><hr> <a name="ntp_002dwait-Authors"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Notes">ntp-wait Notes</a>, Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.6 ntp-wait Authors</h4> <div class="node"> <p><hr> <a name="ntp_002dwait-Notes"></a>Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-Authors">ntp-wait Authors</a>, Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> <br> </div> <h4 class="subsection">0.1.7 ntp-wait Notes</h4> </body></html>