1<html lang="en"> 2<head> 3<title>Ntp-wait User's Manual</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Ntp-wait User's Manual"> 6<meta name="generator" content="makeinfo 4.7"> 7<link title="Top" rel="top" href="#Top"> 8<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> 9<meta http-equiv="Content-Style-Type" content="text/css"> 10<style type="text/css"><!-- 11 pre.display { font-family:inherit } 12 pre.format { font-family:inherit } 13 pre.smalldisplay { font-family:inherit; font-size:smaller } 14 pre.smallformat { font-family:inherit; font-size:smaller } 15 pre.smallexample { font-size:smaller } 16 pre.smalllisp { font-size:smaller } 17 span.sc { font-variant:small-caps } 18 span.roman { font-family: serif; font-weight: normal; } 19--></style> 20</head> 21<body> 22<h1 class="settitle">Ntp-wait User's Manual</h1> 23<div class="node"> 24<p><hr> 25<a name="Top"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Description">ntp-wait Description</a>, 26Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>, 27Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> 28<br> 29</div> 30 31 <p>This document describes the use of the NTP Project's <code>ntp-wait</code> program. 32 33 <p>If there are time-sensitive applications, 34the proper sequence of events is to 35run <code>ntpd -g</code> as early as possible, 36then invoke all of the non-time-sensitive process, 37run <code>ntp-wait</code> to block 38until the system's time has stabilized and synchronized, 39and only then start any applicaitons (like database servers) that require 40accurate and stable time. 41 42 <p>This document applies to version 4.2.8p10 of <code>ntp-wait</code>. 43 44<div class="shortcontents"> 45<h2>Short Contents</h2> 46<ul> 47</ul> 48</div> 49 50<ul class="menu"> 51<li><a accesskey="1" href="#ntp_002dwait-Description">ntp-wait Description</a>: Description 52<li><a accesskey="2" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>: Invoking ntp-wait 53</ul> 54 55<div class="node"> 56<p><hr> 57<a name="ntp_002dwait-Invocation"></a> 58<br> 59</div> 60 61<h3 class="section">0.1 Invoking ntp-wait</h3> 62 63<p><a name="index-ntp_002dwait-1"></a><a name="index-Wait-for-ntpd-to-stabilize-the-system-clock-2"></a> 64 65 <p><code>ntp-wait</code> 66will send at most 67<kbd>num-tries</kbd> 68queries to 69<code>ntpd(8)</code>, 70sleeping for 71<kbd>secs-between-tries</kbd> 72after each status return that says 73<code>ntpd(8)</code> 74has not yet produced a synchronized and stable system clock. 75 76 <p><code>ntp-wait</code> 77will do this quietly, unless the 78<code>-v</code> 79flag is provided. 80This can be useful at boot time, to delay the boot sequence until after 81<kbd>ntpd</kbd> <kbd>-g</kbd> 82has set the time. 83 84 <p>This section was generated by <strong>AutoGen</strong>, 85using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-wait</code> program. 86 87<ul class="menu"> 88<li><a accesskey="1" href="#ntp_002dwait-usage">ntp-wait usage</a>: ntp-wait help/usage (<span class="option">--help</span>) 89<li><a accesskey="2" href="#ntp_002dwait-tries">ntp-wait tries</a>: tries option (-n) 90<li><a accesskey="3" href="#ntp_002dwait-sleep">ntp-wait sleep</a>: sleep option (-s) 91<li><a accesskey="4" href="#ntp_002dwait-verbose">ntp-wait verbose</a>: verbose option (-v) 92<li><a accesskey="5" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>: exit status 93<li><a accesskey="6" href="#ntp_002dwait-Authors">ntp-wait Authors</a>: Authors 94<li><a accesskey="7" href="#ntp_002dwait-Notes">ntp-wait Notes</a>: Notes 95</ul> 96 97<div class="node"> 98<p><hr> 99<a name="ntp_002dwait-usage"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-tries">ntp-wait tries</a>, 100Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 101<br> 102</div> 103 104<h4 class="subsection">0.1.1 ntp-wait help/usage (<span class="option">--help</span>)</h4> 105 106<p><a name="index-ntp_002dwait-help-3"></a> 107This is the automatically generated usage text for ntp-wait. 108 109 <p>The text printed is the same whether selected with the <code>help</code> option 110(<span class="option">--help</span>) or the <code>more-help</code> option (<span class="option">--more-help</span>). <code>more-help</code> will print 111the usage text by passing it through a pager program. 112<code>more-help</code> is disabled on platforms without a working 113<code>fork(2)</code> function. The <code>PAGER</code> environment variable is 114used to select the program, defaulting to <span class="file">more</span>. Both will exit 115with a status code of 0. 116 117<pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p10 118USAGE: ntp-wait [ -<flag> [<val>] | --<name>[{=| }<val>] ]... 119 120 -n, --tries=num Number of times to check ntpd 121 -s, --sleep=num How long to sleep between tries 122 -v, --verbose Be verbose 123 -?, --help Display usage information and exit 124 --more-help Pass the extended usage text through a pager 125 126Options are specified by doubled hyphens and their name or by a single 127hyphen and the flag character. 128</pre> 129 <div class="node"> 130<p><hr> 131<a name="ntp_002dwait-tries"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-sleep">ntp-wait sleep</a>, 132Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-usage">ntp-wait usage</a>, 133Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 134<br> 135</div> 136 137<h4 class="subsection">0.1.2 tries option (-n)</h4> 138 139<p><a name="index-ntp_002dwait_002dtries-4"></a> 140This is the “number of times to check ntpd” option. 141This option takes a number argument. 142 The maximum number of times we will check <code>ntpd</code> to see if 143 it has been able to synchronize and stabilize the system clock. 144<div class="node"> 145<p><hr> 146<a name="ntp_002dwait-sleep"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-verbose">ntp-wait verbose</a>, 147Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-tries">ntp-wait tries</a>, 148Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 149<br> 150</div> 151 152<h4 class="subsection">0.1.3 sleep option (-s)</h4> 153 154<p><a name="index-ntp_002dwait_002dsleep-5"></a> 155This is the “how long to sleep between tries” option. 156This option takes a number argument <span class="file">secs-between-tries</span>. 157 We will sleep for <span class="file">secs-between-tries</span> after each query 158 of <code>ntpd</code> that returns "the time is not yet stable". 159<div class="node"> 160<p><hr> 161<a name="ntp_002dwait-verbose"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>, 162Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-sleep">ntp-wait sleep</a>, 163Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 164<br> 165</div> 166 167<h4 class="subsection">0.1.4 verbose option (-v)</h4> 168 169<p><a name="index-ntp_002dwait_002dverbose-6"></a> 170This is the “be verbose” option. 171 By default, <code>ntp-wait</code> is silent. 172 With this option, <code>ntp-wait</code> will provide status information. 173<div class="node"> 174<p><hr> 175<a name="ntp_002dwait-exit-status"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Authors">ntp-wait Authors</a>, 176Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-verbose">ntp-wait verbose</a>, 177Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 178<br> 179</div> 180 181<h4 class="subsection">0.1.5 ntp-wait exit status</h4> 182 183<p>One of the following exit values will be returned: 184 <dl> 185<dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution. 186<br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid. 187</dl> 188 <div class="node"> 189<p><hr> 190<a name="ntp_002dwait-Authors"></a>Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Notes">ntp-wait Notes</a>, 191Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>, 192Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 193<br> 194</div> 195 196<h4 class="subsection">0.1.6 ntp-wait Authors</h4> 197 198<div class="node"> 199<p><hr> 200<a name="ntp_002dwait-Notes"></a>Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-Authors">ntp-wait Authors</a>, 201Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 202<br> 203</div> 204 205<h4 class="subsection">0.1.7 ntp-wait Notes</h4> 206 207</body></html> 208 209