1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- Created by GNU Texinfo 6.6, http://www.gnu.org/software/texinfo/ --> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 6<title>Ntp-wait User’s Manual</title> 7 8<meta name="description" content="Ntp-wait User’s Manual"> 9<meta name="keywords" content="Ntp-wait User’s Manual"> 10<meta name="resource-type" content="document"> 11<meta name="distribution" content="global"> 12<meta name="Generator" content="makeinfo"> 13<link href="#Top" rel="start" title="Top"> 14<link href="dir.html#Top" rel="up" title="(dir)"> 15<style type="text/css"> 16<!-- 17a.summary-letter {text-decoration: none} 18blockquote.indentedblock {margin-right: 0em} 19div.display {margin-left: 3.2em} 20div.example {margin-left: 3.2em} 21div.lisp {margin-left: 3.2em} 22kbd {font-style: oblique} 23pre.display {font-family: inherit} 24pre.format {font-family: inherit} 25pre.menu-comment {font-family: serif} 26pre.menu-preformatted {font-family: serif} 27span.nolinebreak {white-space: nowrap} 28span.roman {font-family: initial; font-weight: normal} 29span.sansserif {font-family: sans-serif; font-weight: normal} 30ul.no-bullet {list-style: none} 31--> 32</style> 33 34 35</head> 36 37<body lang="en"> 38<h1 class="settitle" align="center">Ntp-wait User’s Manual</h1> 39 40 41 42 43 44<span id="Top"></span><div class="header"> 45<p> 46Previous: <a href="dir.html#Top" accesskey="p" rel="prev">(dir)</a>, Up: <a href="dir.html#Top" accesskey="u" rel="up">(dir)</a> </p> 47</div> 48<h1 class="node-heading">Top</h1> 49 50<p>This document describes the use of the NTP Project’s <code>ntp-wait</code> program. 51</p> 52<p>If there are time-sensitive applications, 53the proper sequence of events is to 54run <code>ntpd -g</code> as early as possible, 55then invoke all of the non-time-sensitive process, 56run <code>ntp-wait</code> to block 57until the system’s time has stabilized and synchronized, 58and only then start any applicaitons (like database servers) that require 59accurate and stable time. 60</p> 61<p>This document applies to version 4.2.8p17 of <code>ntp-wait</code>. 62</p> 63<span id="SEC_Overview"></span> 64<h2 class="shortcontents-heading">Short Table of Contents</h2> 65 66<div class="shortcontents"> 67<li><a id="stoc-Invoking-ntp_002dwait" href="#toc-Invoking-ntp_002dwait">1 Invoking ntp-wait</a></li> 68 69</div> 70 71 72<table class="menu" border="0" cellspacing="0"> 73<tr><td align="left" valign="top">• ntp-wait Description</td><td> </td><td align="left" valign="top">Description 74</td></tr> 75<tr><td align="left" valign="top">• <a href="#ntp_002dwait-Invocation" accesskey="2">ntp-wait Invocation</a></td><td> </td><td align="left" valign="top">Invoking ntp-wait 76</td></tr> 77</table> 78 79<hr> 80<span id="ntp_002dwait-Invocation"></span><div class="header"> 81<p> 82Up: <a href="#Top" accesskey="u" rel="up">Top</a> </p> 83</div> 84<span id="Invoking-ntp_002dwait"></span><h3 class="section">1 Invoking ntp-wait</h3> 85<span id="index-ntp_002dwait"></span> 86<span id="index-Wait-for-ntpd-to-stabilize-the-system-clock"></span> 87 88 89 90<p><code>ntp-wait</code> 91will send at most 92<kbd>num-tries</kbd> 93queries to 94<code>ntpd(8)</code>, 95sleeping for 96<kbd>secs-between-tries</kbd> 97after each status return that says 98<code>ntpd(8)</code> 99has not yet produced a synchronized and stable system clock. 100</p> 101<p><code>ntp-wait</code> 102will do this quietly, unless the 103<code>-v</code> 104flag is provided. 105This can be useful at boot time, to delay the boot sequence until after 106<kbd>ntpd</kbd> <kbd>-g</kbd> 107has set the time. 108</p> 109<p>This section was generated by <strong>AutoGen</strong>, 110using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-wait</code> program. 111</p> 112<table class="menu" border="0" cellspacing="0"> 113<tr><td align="left" valign="top">• <a href="#ntp_002dwait-usage" accesskey="1">ntp-wait usage</a></td><td> </td><td align="left" valign="top">ntp-wait help/usage (<samp>--help</samp>) 114</td></tr> 115<tr><td align="left" valign="top">• <a href="#ntp_002dwait-tries" accesskey="2">ntp-wait tries</a></td><td> </td><td align="left" valign="top">tries option (-n) 116</td></tr> 117<tr><td align="left" valign="top">• <a href="#ntp_002dwait-sleep" accesskey="3">ntp-wait sleep</a></td><td> </td><td align="left" valign="top">sleep option (-s) 118</td></tr> 119<tr><td align="left" valign="top">• <a href="#ntp_002dwait-verbose" accesskey="4">ntp-wait verbose</a></td><td> </td><td align="left" valign="top">verbose option (-v) 120</td></tr> 121<tr><td align="left" valign="top">• <a href="#ntp_002dwait-exit-status" accesskey="5">ntp-wait exit status</a></td><td> </td><td align="left" valign="top">exit status 122</td></tr> 123<tr><td align="left" valign="top">• <a href="#ntp_002dwait-Authors" accesskey="6">ntp-wait Authors</a></td><td> </td><td align="left" valign="top">Authors 124</td></tr> 125<tr><td align="left" valign="top">• <a href="#ntp_002dwait-Notes" accesskey="7">ntp-wait Notes</a></td><td> </td><td align="left" valign="top">Notes 126</td></tr> 127</table> 128 129<hr> 130<span id="ntp_002dwait-usage"></span><div class="header"> 131<p> 132Next: <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> </p> 133</div> 134<span id="ntp_002dwait-help_002fusage-_0028_002d_002dhelp_0029"></span><h4 class="subsection">1.1 ntp-wait help/usage (<samp>--help</samp>)</h4> 135<span id="index-ntp_002dwait-help"></span> 136 137<p>This is the automatically generated usage text for ntp-wait. 138</p> 139<p>The text printed is the same whether selected with the <code>help</code> option 140(<samp>--help</samp>) or the <code>more-help</code> option (<samp>--more-help</samp>). <code>more-help</code> will print 141the usage text by passing it through a pager program. 142<code>more-help</code> is disabled on platforms without a working 143<code>fork(2)</code> function. The <code>PAGER</code> environment variable is 144used to select the program, defaulting to <samp>more</samp>. Both will exit 145with a status code of 0. 146</p> 147<div class="example"> 148<pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p17 149USAGE: ntp-wait [ -<flag> [<val>] | --<name>[{=| }<val>] ]... 150 151 -n, --tries=num Number of times to check ntpd 152 -s, --sleep=num How long to sleep between tries 153 -v, --verbose Be verbose 154 -?, --help Display usage information and exit 155 --more-help Pass the extended usage text through a pager 156 157Options are specified by doubled hyphens and their name or by a single 158hyphen and the flag character. 159</pre></div> 160 161<hr> 162<span id="ntp_002dwait-tries"></span><div class="header"> 163<p> 164Next: <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> </p> 165</div> 166<span id="tries-option-_0028_002dn_0029"></span><h4 class="subsection">1.2 tries option (-n)</h4> 167<span id="index-ntp_002dwait_002dtries"></span> 168 169<p>This is the “number of times to check ntpd” option. 170This option takes a number argument. 171 The maximum number of times we will check <code>ntpd</code> to see if 172 it has been able to synchronize and stabilize the system clock. 173</p><hr> 174<span id="ntp_002dwait-sleep"></span><div class="header"> 175<p> 176Next: <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> </p> 177</div> 178<span id="sleep-option-_0028_002ds_0029"></span><h4 class="subsection">1.3 sleep option (-s)</h4> 179<span id="index-ntp_002dwait_002dsleep"></span> 180 181<p>This is the “how long to sleep between tries” option. 182This option takes a number argument <samp>secs-between-tries</samp>. 183 We will sleep for <samp>secs-between-tries</samp> after each query 184 of <code>ntpd</code> that returns "the time is not yet stable". 185</p><hr> 186<span id="ntp_002dwait-verbose"></span><div class="header"> 187<p> 188Next: <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> </p> 189</div> 190<span id="verbose-option-_0028_002dv_0029"></span><h4 class="subsection">1.4 verbose option (-v)</h4> 191<span id="index-ntp_002dwait_002dverbose"></span> 192 193<p>This is the “be verbose” option. 194 By default, <code>ntp-wait</code> is silent. 195 With this option, <code>ntp-wait</code> will provide status information. 196</p><hr> 197<span id="ntp_002dwait-exit-status"></span><div class="header"> 198<p> 199Next: <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> </p> 200</div> 201<span id="ntp_002dwait-exit-status-1"></span><h4 class="subsection">1.5 ntp-wait exit status</h4> 202 203<p>One of the following exit values will be returned: 204</p><dl compact="compact"> 205<dt>‘<samp>0 (EXIT_SUCCESS)</samp>’</dt> 206<dd><p>Successful program execution. 207</p></dd> 208<dt>‘<samp>1 (EXIT_FAILURE)</samp>’</dt> 209<dd><p>The operation failed or the command syntax was not valid. 210</p></dd> 211</dl> 212<hr> 213<span id="ntp_002dwait-Authors"></span><div class="header"> 214<p> 215Next: <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> </p> 216</div> 217<span id="ntp_002dwait-Authors-1"></span><h4 class="subsection">1.6 ntp-wait Authors</h4> 218<hr> 219<span id="ntp_002dwait-Notes"></span><div class="header"> 220<p> 221Previous: <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> </p> 222</div> 223<span id="ntp_002dwait-Notes-1"></span><h4 class="subsection">1.7 ntp-wait Notes</h4> 224<hr> 225 226 227 228</body> 229</html> 230