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 4.8"> 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 span.sansserif { font-family:sans-serif; font-weight:normal; } 20--></style> 21</head> 22<body> 23<h1 class="settitle">Ntp-wait User's Manual</h1> 24<div class="node"> 25<p><hr> 26<a name="Top"></a> 27Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Description">ntp-wait Description</a>, 28Previous: <a rel="previous" accesskey="p" href="#dir">(dir)</a>, 29Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> 30 31</div> 32 33 <p>This document describes the use of the NTP Project's <code>ntp-wait</code> program. 34 35 <p>If there are time-sensitive applications, 36the proper sequence of events is to 37run <code>ntpd -g</code> as early as possible, 38then invoke all of the non-time-sensitive process, 39run <code>ntp-wait</code> to block 40until the system's time has stabilized and synchronized, 41and only then start any applicaitons (like database servers) that require 42accurate and stable time. 43 44 <p>This document applies to version 4.2.8p5 of <code>ntp-wait</code>. 45 46<div class="shortcontents"> 47<h2>Short Contents</h2> 48<ul> 49</ul> 50</div> 51 52<ul class="menu"> 53<li><a accesskey="1" href="#ntp_002dwait-Description">ntp-wait Description</a>: Description 54<li><a accesskey="2" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a>: Invoking ntp-wait 55</ul> 56 57<div class="node"> 58<p><hr> 59<a name="ntp-wait-Invocation"></a> 60<a name="ntp_002dwait-Invocation"></a> 61 62 63</div> 64 65<h3 class="section">0.1 Invoking ntp-wait</h3> 66 67<p><a name="index-ntp_002dwait-1"></a><a name="index-Wait-for-ntpd-to-stabilize-the-system-clock-2"></a> 68 69 <p><code>ntp-wait</code> 70will send at most 71<kbd>num-tries</kbd> 72queries to 73<code>ntpd(8)</code>, 74sleeping for 75<kbd>secs-between-tries</kbd> 76after each status return that says 77<code>ntpd(8)</code> 78has not yet produced a synchronized and stable system clock. 79 80 <p><code>ntp-wait</code> 81will do this quietly, unless the 82<code>-v</code> 83flag is provided. 84This can be useful at boot time, to delay the boot sequence until after 85<kbd>ntpd</kbd> <kbd>-g</kbd> 86has set the time. 87 88 <p>This section was generated by <strong>AutoGen</strong>, 89using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-wait</code> program. 90 91<ul class="menu"> 92<li><a accesskey="1" href="#ntp_002dwait-usage">ntp-wait usage</a>: ntp-wait help/usage (<samp><span class="option">--help</span></samp>) 93<li><a accesskey="2" href="#ntp_002dwait-tries">ntp-wait tries</a>: tries option (-n) 94<li><a accesskey="3" href="#ntp_002dwait-sleep">ntp-wait sleep</a>: sleep option (-s) 95<li><a accesskey="4" href="#ntp_002dwait-verbose">ntp-wait verbose</a>: verbose option (-v) 96<li><a accesskey="5" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>: exit status 97<li><a accesskey="6" href="#ntp_002dwait-Authors">ntp-wait Authors</a>: Authors 98<li><a accesskey="7" href="#ntp_002dwait-Notes">ntp-wait Notes</a>: Notes 99</ul> 100 101<div class="node"> 102<p><hr> 103<a name="ntp-wait-usage"></a> 104<a name="ntp_002dwait-usage"></a> 105Next: <a rel="next" accesskey="n" href="#ntp_002dwait-tries">ntp-wait tries</a>, 106Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 107 108</div> 109 110<h4 class="subsection">0.1.1 ntp-wait help/usage (<samp><span class="option">--help</span></samp>)</h4> 111 112<p><a name="index-ntp_002dwait-help-3"></a> 113This is the automatically generated usage text for ntp-wait. 114 115 <p>The text printed is the same whether selected with the <code>help</code> option 116(<samp><span class="option">--help</span></samp>) or the <code>more-help</code> option (<samp><span class="option">--more-help</span></samp>). <code>more-help</code> will print 117the usage text by passing it through a pager program. 118<code>more-help</code> is disabled on platforms without a working 119<code>fork(2)</code> function. The <code>PAGER</code> environment variable is 120used to select the program, defaulting to <samp><span class="file">more</span></samp>. Both will exit 121with a status code of 0. 122 123<pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p5 124USAGE: ntp-wait [ -<flag> [<val>] | --<name>[{=| }<val>] ]... 125 126 -n, --tries=num Number of times to check ntpd 127 -s, --sleep=num How long to sleep between tries 128 -v, --verbose Be verbose 129 -?, --help Display usage information and exit 130 --more-help Pass the extended usage text through a pager 131 132Options are specified by doubled hyphens and their name or by a single 133hyphen and the flag character. 134</pre> 135 <div class="node"> 136<p><hr> 137<a name="ntp-wait-tries"></a> 138<a name="ntp_002dwait-tries"></a> 139Next: <a rel="next" accesskey="n" href="#ntp_002dwait-sleep">ntp-wait sleep</a>, 140Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-usage">ntp-wait usage</a>, 141Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 142 143</div> 144 145<h4 class="subsection">0.1.2 tries option (-n)</h4> 146 147<p><a name="index-ntp_002dwait_002dtries-4"></a> 148This is the “number of times to check ntpd” option. 149This option takes a number argument. 150 The maximum number of times we will check <code>ntpd</code> to see if 151 it has been able to synchronize and stabilize the system clock. 152<div class="node"> 153<p><hr> 154<a name="ntp-wait-sleep"></a> 155<a name="ntp_002dwait-sleep"></a> 156Next: <a rel="next" accesskey="n" href="#ntp_002dwait-verbose">ntp-wait verbose</a>, 157Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-tries">ntp-wait tries</a>, 158Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 159 160</div> 161 162<h4 class="subsection">0.1.3 sleep option (-s)</h4> 163 164<p><a name="index-ntp_002dwait_002dsleep-5"></a> 165This is the “how long to sleep between tries” option. 166This option takes a number argument <samp><span class="file">secs-between-tries</span></samp>. 167 We will sleep for <samp><span class="file">secs-between-tries</span></samp> after each query 168 of <code>ntpd</code> that returns "the time is not yet stable". 169<div class="node"> 170<p><hr> 171<a name="ntp-wait-verbose"></a> 172<a name="ntp_002dwait-verbose"></a> 173Next: <a rel="next" accesskey="n" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>, 174Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-sleep">ntp-wait sleep</a>, 175Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 176 177</div> 178 179<h4 class="subsection">0.1.4 verbose option (-v)</h4> 180 181<p><a name="index-ntp_002dwait_002dverbose-6"></a> 182This is the “be verbose” option. 183 By default, <code>ntp-wait</code> is silent. 184 With this option, <code>ntp-wait</code> will provide status information. 185<div class="node"> 186<p><hr> 187<a name="ntp-wait-exit-status"></a> 188<a name="ntp_002dwait-exit-status"></a> 189Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Authors">ntp-wait Authors</a>, 190Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-verbose">ntp-wait verbose</a>, 191Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 192 193</div> 194 195<h4 class="subsection">0.1.5 ntp-wait exit status</h4> 196 197<p>One of the following exit values will be returned: 198 <dl> 199<dt>`<samp><span class="samp">0 (EXIT_SUCCESS)</span></samp>'<dd>Successful program execution. 200<br><dt>`<samp><span class="samp">1 (EXIT_FAILURE)</span></samp>'<dd>The operation failed or the command syntax was not valid. 201</dl> 202 <div class="node"> 203<p><hr> 204<a name="ntp-wait-Authors"></a> 205<a name="ntp_002dwait-Authors"></a> 206Next: <a rel="next" accesskey="n" href="#ntp_002dwait-Notes">ntp-wait Notes</a>, 207Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-exit-status">ntp-wait exit status</a>, 208Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 209 210</div> 211 212<h4 class="subsection">0.1.6 ntp-wait Authors</h4> 213 214<div class="node"> 215<p><hr> 216<a name="ntp-wait-Notes"></a> 217<a name="ntp_002dwait-Notes"></a> 218Previous: <a rel="previous" accesskey="p" href="#ntp_002dwait-Authors">ntp-wait Authors</a>, 219Up: <a rel="up" accesskey="u" href="#ntp_002dwait-Invocation">ntp-wait Invocation</a> 220 221</div> 222 223<h4 class="subsection">0.1.7 ntp-wait Notes</h4> 224 225</body></html> 226 227