contrib/ntp/scripts/ntp-wait/ntp-wait.html

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  47 <h1 class="settitle" align="center">Ntp-wait User&rsquo;s Manual</h1>
  48
  49
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  54 <div class="header">
  55 <p>
  56 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>
  57 </div>
  58 <h1 class="node-heading">Top</h1>
  59
  60 <p>This document describes the use of the NTP Project&rsquo;s <code>ntp-wait</code> program.
  61 </p>
  62 <p>If there are time-sensitive applications,
  63 the proper sequence of events is to
  64 run <code>ntpd -g</code> as early as possible,
  65 then invoke all of the non-time-sensitive process,
  66 run <code>ntp-wait</code> to block
  67 until the system&rsquo;s time has stabilized and synchronized,
  68 and only then start any applicaitons (like database servers) that require
  69 accurate and stable time.
  70 </p>
  71 <p>This document applies to version 4.2.8p14 of <code>ntp-wait</code>.
  72 </p>
  73 <a name="SEC_Overview"></a>
  74 <h2 class="shortcontents-heading">Short Table of Contents</h2>
  75
  76 <div class="shortcontents">
  77 <li><a name="stoc-Invoking-ntp_002dwait" href="#toc-Invoking-ntp_002dwait">1 Invoking ntp-wait</a></li>
  78
  79 </div>
  80
  81
  82 <table class="menu" border="0" cellspacing="0">
  83 <tr><td align="left" valign="top">&bull; ntp-wait Description:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">Description
  84 </td></tr>
  85 <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
  86 </td></tr>
  87 </table>
  88
  89 <hr>
  90 <a name="ntp_002dwait-Invocation"></a>
  91 <div class="header">
  92 <p>
  93 Up: <a href="#Top" accesskey="u" rel="up">Top</a> &nbsp; </p>
  94 </div>
  95 <a name="Invoking-ntp_002dwait"></a>
  96 <h3 class="section">1 Invoking ntp-wait</h3>
  97 <a name="index-ntp_002dwait"></a>
  98 <a name="index-Wait-for-ntpd-to-stabilize-the-system-clock"></a>
  99
 100
 101
 102 <p><code>ntp-wait</code>
 103 will send at most
 104 <kbd>num-tries</kbd>
 105 queries to
 106 <code>ntpd(8)</code>,
 107 sleeping for
 108 <kbd>secs-between-tries</kbd>
 109 after each status return that says
 110 <code>ntpd(8)</code>
 111 has not yet produced a synchronized and stable system clock.
 112 </p>
 113 <p><code>ntp-wait</code>
 114 will do this quietly, unless the
 115 <code>-v</code>
 116 flag is provided.
 117 This can be useful at boot time, to delay the boot sequence until after
 118 <kbd>ntpd</kbd> <kbd>-g</kbd>
 119 has set the time.
 120 </p>
 121 <p>This section was generated by <strong>AutoGen</strong>,
 122 using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-wait</code> program.
 123 </p>
 124 <table class="menu" border="0" cellspacing="0">
 125 <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>)
 126 </td></tr>
 127 <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)
 128 </td></tr>
 129 <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)
 130 </td></tr>
 131 <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)
 132 </td></tr>
 133 <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
 134 </td></tr>
 135 <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
 136 </td></tr>
 137 <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
 138 </td></tr>
 139 </table>
 140
 141 <hr>
 142 <a name="ntp_002dwait-usage"></a>
 143 <div class="header">
 144 <p>
 145 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>
 146 </div>
 147 <a name="ntp_002dwait-help_002fusage-_0028_002d_002dhelp_0029"></a>
 148 <h4 class="subsection">1.1 ntp-wait help/usage (<samp>--help</samp>)</h4>
 149 <a name="index-ntp_002dwait-help"></a>
 150
 151 <p>This is the automatically generated usage text for ntp-wait.
 152 </p>
 153 <p>The text printed is the same whether selected with the <code>help</code> option
 154 (<samp>--help</samp>) or the <code>more-help</code> option (<samp>--more-help</samp>).  <code>more-help</code> will print
 155 the usage text by passing it through a pager program.
 156 <code>more-help</code> is disabled on platforms without a working
 157 <code>fork(2)</code> function.  The <code>PAGER</code> environment variable is
 158 used to select the program, defaulting to <samp>more</samp>.  Both will exit
 159 with a status code of 0.
 160 </p>
 161 <div class="example">
 162 <pre class="example">ntp-wait - Wait for ntpd to stabilize the system clock - Ver. 4.2.8p14
 163 USAGE: ntp-wait [ -&lt;flag&gt; [&lt;val&gt;] | --&lt;name&gt;[{=| }&lt;val&gt;] ]...
 164
 165     -n, --tries=num              Number of times to check ntpd
 166     -s, --sleep=num              How long to sleep between tries
 167     -v, --verbose                Be verbose
 168     -?, --help                   Display usage information and exit
 169         --more-help              Pass the extended usage text through a pager
 170
 171 Options are specified by doubled hyphens and their name or by a single
 172 hyphen and the flag character.
 173 </pre></div>
 174
 175 <hr>
 176 <a name="ntp_002dwait-tries"></a>
 177 <div class="header">
 178 <p>
 179 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>
 180 </div>
 181 <a name="tries-option-_0028_002dn_0029"></a>
 182 <h4 class="subsection">1.2 tries option (-n)</h4>
 183 <a name="index-ntp_002dwait_002dtries"></a>
 184
 185 <p>This is the &ldquo;number of times to check ntpd&rdquo; option.
 186 This option takes a number argument.
 187         The maximum number of times we will check <code>ntpd</code> to see if
 188         it has been able to synchronize and stabilize the system clock.
 189 </p><hr>
 190 <a name="ntp_002dwait-sleep"></a>
 191 <div class="header">
 192 <p>
 193 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>
 194 </div>
 195 <a name="sleep-option-_0028_002ds_0029"></a>
 196 <h4 class="subsection">1.3 sleep option (-s)</h4>
 197 <a name="index-ntp_002dwait_002dsleep"></a>
 198
 199 <p>This is the &ldquo;how long to sleep between tries&rdquo; option.
 200 This option takes a number argument <samp>secs-between-tries</samp>.
 201         We will sleep for <samp>secs-between-tries</samp> after each query
 202         of <code>ntpd</code> that returns &quot;the time is not yet stable&quot;.
 203 </p><hr>
 204 <a name="ntp_002dwait-verbose"></a>
 205 <div class="header">
 206 <p>
 207 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>
 208 </div>
 209 <a name="verbose-option-_0028_002dv_0029"></a>
 210 <h4 class="subsection">1.4 verbose option (-v)</h4>
 211 <a name="index-ntp_002dwait_002dverbose"></a>
 212
 213 <p>This is the &ldquo;be verbose&rdquo; option.
 214         By default, <code>ntp-wait</code> is silent.
 215         With this option, <code>ntp-wait</code> will provide status information.
 216 </p><hr>
 217 <a name="ntp_002dwait-exit-status"></a>
 218 <div class="header">
 219 <p>
 220 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>
 221 </div>
 222 <a name="ntp_002dwait-exit-status-1"></a>
 223 <h4 class="subsection">1.5 ntp-wait exit status</h4>
 224
 225 <p>One of the following exit values will be returned:
 226 </p><dl compact="compact">
 227 <dt>&lsquo;<samp>0 (EXIT_SUCCESS)</samp>&rsquo;</dt>
 228 <dd><p>Successful program execution.
 229 </p></dd>
 230 <dt>&lsquo;<samp>1 (EXIT_FAILURE)</samp>&rsquo;</dt>
 231 <dd><p>The operation failed or the command syntax was not valid.
 232 </p></dd>
 233 </dl>
 234 <hr>
 235 <a name="ntp_002dwait-Authors"></a>
 236 <div class="header">
 237 <p>
 238 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>
 239 </div>
 240 <a name="ntp_002dwait-Authors-1"></a>
 241 <h4 class="subsection">1.6 ntp-wait Authors</h4>
 242 <hr>
 243 <a name="ntp_002dwait-Notes"></a>
 244 <div class="header">
 245 <p>
 246 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>
 247 </div>
 248 <a name="ntp_002dwait-Notes-1"></a>
 249 <h4 class="subsection">1.7 ntp-wait Notes</h4>
 250 <hr>
 251
 252
 253
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 255 </html>