1<html lang="en"> 2<head> 3<title>Sntp User's Manual</title> 4<meta http-equiv="Content-Type" content="text/html"> 5<meta name="description" content="Sntp 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">Sntp User's Manual</h1> 23<div class="node"> 24<p><hr> 25<a name="Top"></a>Next: <a rel="next" accesskey="n" href="#sntp-Description">sntp 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<h2 class="unnumbered">Simple Network Time Protocol User Manual</h2> 32 33<p>This document describes the use of the NTP Project's <code>sntp</code> program, 34that can be used to query a Network Time Protocol (NTP) server and 35display the time offset of the system clock relative to the server 36clock. Run as root, it can correct the system clock to this offset as 37well. It can be run as an interactive command or from a cron job. 38 39 <p>This document applies to version 4.2.8p10 of <code>sntp</code>. 40 41 <p>The program implements the SNTP protocol as defined by RFC 5905, the NTPv4 42IETF specification. 43 44 <div class="shortcontents"> 45<h2>Short Contents</h2> 46<ul> 47<a href="#Top">Simple Network Time Protocol User Manual</a> 48</ul> 49</div> 50 51<ul class="menu"> 52<li><a accesskey="1" href="#sntp-Description">sntp Description</a>: Description 53<li><a accesskey="2" href="#sntp-Invocation">sntp Invocation</a>: Invoking sntp 54<li><a accesskey="3" href="#Usage">Usage</a>: Usage 55</ul> 56 57<div class="node"> 58<p><hr> 59<a name="sntp-Description"></a> 60<br> 61</div> 62 63<!-- node-name, next, previous, up --> 64<h3 class="section">Description</h3> 65 66<p>By default, <code>sntp</code> writes the local data and time (i.e., not UTC) to the 67standard output in the format: 68 69<pre class="example"> 1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs 70</pre> 71 <p>where 72YYYY-MM-DD HH:MM:SS.SUBSEC is the local date and time, 73(+0800) is the local timezone adjustment (so we would add 8 hours and 0 minutes to convert the reported local time to UTC), 74and 75the +4.567 +/- 0.089 secs indicates the time offset and 76error bound of the system clock relative to the server clock. 77 78<div class="node"> 79<p><hr> 80<a name="sntp-Invocation"></a> 81<br> 82</div> 83 84<h3 class="section">Invoking sntp</h3> 85 86<p><a name="index-sntp-1"></a><a name="index-standard-Simple-Network-Time-Protocol-client-program-2"></a> 87 88 <p><code>sntp</code> 89can be used as an SNTP client to query a NTP or SNTP server and either display 90the time or set the local system's time (given suitable privilege). It can be 91run as an interactive command or from a 92<code>cron</code> 93job. 94 95 <p>NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol) 96are defined and described by RFC 5905. 97 98 <p>The default is to write the estimated correct local date and time (i.e. not 99UTC) to the standard output in a format like: 100 101 <p><code>'1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 [host] IP sN'</code> 102 103 <p>where the 104<code>'(+0800)'</code> 105means that to get to UTC from the reported local time one must 106add 8 hours and 0 minutes, 107the 108<code>'+4.567'</code> 109indicates the local clock is 4.567 seconds behind the correct time 110(so 4.567 seconds must be added to the local clock to get it to be correct). 111Note that the number of decimals printed for this value will change 112based on the reported precision of the server. 113<code>'+/- 0.089'</code> 114is the reported 115<em>synchronization</em> <em>distance</em> 116(in seconds), which represents the maximum error due to all causes. 117If the server does not report valid data needed to calculate the 118synchronization distance, this will be reported as 119<code>'+/- ?'</code>. 120If the 121<em>host</em> 122is different from the 123<em>IP</em>, 124both will be displayed. 125Otherwise, only the 126<em>IP</em> 127is displayed. 128Finally, the 129<em>stratum</em> 130of the host is reported 131and the leap indicator is decoded and displayed. 132 133 <p>This section was generated by <strong>AutoGen</strong>, 134using the <code>agtexi-cmd</code> template and the option descriptions for the <code>sntp</code> program. 135This software is released under the NTP license, <http://ntp.org/license>. 136 137<ul class="menu"> 138<li><a accesskey="1" href="#sntp-usage">sntp usage</a>: sntp help/usage (<span class="option">--help</span>) 139<li><a accesskey="2" href="#sntp-ipv4">sntp ipv4</a>: ipv4 option (-4) 140<li><a accesskey="3" href="#sntp-ipv6">sntp ipv6</a>: ipv6 option (-6) 141<li><a accesskey="4" href="#sntp-authentication">sntp authentication</a>: authentication option (-a) 142<li><a accesskey="5" href="#sntp-broadcast">sntp broadcast</a>: broadcast option (-b) 143<li><a accesskey="6" href="#sntp-concurrent">sntp concurrent</a>: concurrent option (-c) 144<li><a accesskey="7" href="#sntp-gap">sntp gap</a>: gap option (-g) 145<li><a accesskey="8" href="#sntp-kod">sntp kod</a>: kod option (-K) 146<li><a accesskey="9" href="#sntp-keyfile">sntp keyfile</a>: keyfile option (-k) 147<li><a href="#sntp-logfile">sntp logfile</a>: logfile option (-l) 148<li><a href="#sntp-steplimit">sntp steplimit</a>: steplimit option (-M) 149<li><a href="#sntp-ntpversion">sntp ntpversion</a>: ntpversion option (-o) 150<li><a href="#sntp-usereservedport">sntp usereservedport</a>: usereservedport option (-r) 151<li><a href="#sntp-timeout">sntp timeout</a>: timeout option (-t) 152<li><a href="#sntp-wait">sntp wait</a>: wait option 153<li><a href="#sntp-config">sntp config</a>: presetting/configuring sntp 154<li><a href="#sntp-exit-status">sntp exit status</a>: exit status 155<li><a href="#sntp-Usage">sntp Usage</a>: Usage 156<li><a href="#sntp-Authors">sntp Authors</a>: Authors 157</ul> 158 159<div class="node"> 160<p><hr> 161<a name="sntp-usage"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv4">sntp ipv4</a>, 162Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 163<br> 164</div> 165 166<h4 class="subsection">sntp help/usage (<span class="option">--help</span>)</h4> 167 168<p><a name="index-sntp-help-3"></a> 169This is the automatically generated usage text for sntp. 170 171 <p>The text printed is the same whether selected with the <code>help</code> option 172(<span class="option">--help</span>) or the <code>more-help</code> option (<span class="option">--more-help</span>). <code>more-help</code> will print 173the usage text by passing it through a pager program. 174<code>more-help</code> is disabled on platforms without a working 175<code>fork(2)</code> function. The <code>PAGER</code> environment variable is 176used to select the program, defaulting to <span class="file">more</span>. Both will exit 177with a status code of 0. 178 179<pre class="example">sntp - standard Simple Network Time Protocol client program - Ver. 4.2.8p10 180Usage: sntp [ -<flag> [<val>] | --<name>[{=| }<val>] ]... \ 181 [ hostname-or-IP ...] 182 Flg Arg Option-Name Description 183 -4 no ipv4 Force IPv4 DNS name resolution 184 - prohibits the option 'ipv6' 185 -6 no ipv6 Force IPv6 DNS name resolution 186 - prohibits the option 'ipv4' 187 -a Num authentication Enable authentication with the key auth-keynumber 188 -b Str broadcast Listen to the address specified for broadcast time sync 189 - may appear multiple times 190 -c Str concurrent Concurrently query all IPs returned for host-name 191 - may appear multiple times 192 -d no debug-level Increase debug verbosity level 193 - may appear multiple times 194 -D Num set-debug-level Set the debug verbosity level 195 - may appear multiple times 196 -g Num gap The gap (in milliseconds) between time requests 197 -K Fil kod KoD history filename 198 -k Fil keyfile Look in this file for the key specified with -a 199 -l Fil logfile Log to specified logfile 200 -M Num steplimit Adjustments less than steplimit msec will be slewed 201 - it must be in the range: 202 greater than or equal to 0 203 -o Num ntpversion Send int as our NTP protocol version 204 - it must be in the range: 205 0 to 7 206 -r no usereservedport Use the NTP Reserved Port (port 123) 207 -S no step OK to 'step' the time with settimeofday(2) 208 -s no slew OK to 'slew' the time with adjtime(2) 209 -t Num timeout The number of seconds to wait for responses 210 no wait Wait for pending replies (if not setting the time) 211 - disabled as '--no-wait' 212 - enabled by default 213 opt version output version information and exit 214 -? no help display extended usage information and exit 215 -! no more-help extended usage information passed thru pager 216 -> opt save-opts save the option state to a config file 217 -< Str load-opts load options from a config file 218 - disabled as '--no-load-opts' 219 - may appear multiple times 220 221Options are specified by doubled hyphens and their name or by a single 222hyphen and the flag character. 223 224 225The following option preset mechanisms are supported: 226 - reading file $HOME/.ntprc 227 - reading file ./.ntprc 228 - examining environment variables named SNTP_* 229 230Please send bug reports to: <http://bugs.ntp.org, bugs@ntp.org> 231</pre> 232 <div class="node"> 233<p><hr> 234<a name="sntp-ipv4"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv6">sntp ipv6</a>, 235Previous: <a rel="previous" accesskey="p" href="#sntp-usage">sntp usage</a>, 236Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 237<br> 238</div> 239 240<h4 class="subsection">ipv4 option (-4)</h4> 241 242<p><a name="index-sntp_002dipv4-4"></a> 243This is the “force ipv4 dns name resolution” option. 244 245<p class="noindent">This option has some usage constraints. It: 246 <ul> 247<li>must not appear in combination with any of the following options: 248ipv6. 249</ul> 250 251 <p>Force DNS resolution of the following host names on the command line 252to the IPv4 namespace. 253<div class="node"> 254<p><hr> 255<a name="sntp-ipv6"></a>Next: <a rel="next" accesskey="n" href="#sntp-authentication">sntp authentication</a>, 256Previous: <a rel="previous" accesskey="p" href="#sntp-ipv4">sntp ipv4</a>, 257Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 258<br> 259</div> 260 261<h4 class="subsection">ipv6 option (-6)</h4> 262 263<p><a name="index-sntp_002dipv6-5"></a> 264This is the “force ipv6 dns name resolution” option. 265 266<p class="noindent">This option has some usage constraints. It: 267 <ul> 268<li>must not appear in combination with any of the following options: 269ipv4. 270</ul> 271 272 <p>Force DNS resolution of the following host names on the command line 273to the IPv6 namespace. 274<div class="node"> 275<p><hr> 276<a name="sntp-authentication"></a>Next: <a rel="next" accesskey="n" href="#sntp-broadcast">sntp broadcast</a>, 277Previous: <a rel="previous" accesskey="p" href="#sntp-ipv6">sntp ipv6</a>, 278Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 279<br> 280</div> 281 282<h4 class="subsection">authentication option (-a)</h4> 283 284<p><a name="index-sntp_002dauthentication-6"></a> 285This is the “enable authentication with the key <var>auth-keynumber</var>” option. 286This option takes a number argument <span class="file">auth-keynumber</span>. 287Enable authentication using the key specified in this option's 288argument. The argument of this option is the <span class="option">keyid</span>, a 289number specified in the <span class="option">keyfile</span> as this key's identifier. 290See the <span class="option">keyfile</span> option (<span class="option">-k</span>) for more details. 291<div class="node"> 292<p><hr> 293<a name="sntp-broadcast"></a>Next: <a rel="next" accesskey="n" href="#sntp-concurrent">sntp concurrent</a>, 294Previous: <a rel="previous" accesskey="p" href="#sntp-authentication">sntp authentication</a>, 295Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 296<br> 297</div> 298 299<h4 class="subsection">broadcast option (-b)</h4> 300 301<p><a name="index-sntp_002dbroadcast-7"></a> 302This is the “listen to the address specified for broadcast time sync” option. 303This option takes a string argument <span class="file">broadcast-address</span>. 304 305<p class="noindent">This option has some usage constraints. It: 306 <ul> 307<li>may appear an unlimited number of times. 308</ul> 309 310 <p>If specified <code>sntp</code> will listen to the specified address 311for NTP broadcasts. The default maximum wait time 312can (and probably should) be modified with <span class="option">-t</span>. 313<div class="node"> 314<p><hr> 315<a name="sntp-concurrent"></a>Next: <a rel="next" accesskey="n" href="#sntp-gap">sntp gap</a>, 316Previous: <a rel="previous" accesskey="p" href="#sntp-broadcast">sntp broadcast</a>, 317Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 318<br> 319</div> 320 321<h4 class="subsection">concurrent option (-c)</h4> 322 323<p><a name="index-sntp_002dconcurrent-8"></a> 324This is the “concurrently query all ips returned for host-name” option. 325This option takes a string argument <span class="file">host-name</span>. 326 327<p class="noindent">This option has some usage constraints. It: 328 <ul> 329<li>may appear an unlimited number of times. 330</ul> 331 332 <p>Requests from an NTP "client" to a "server" should never be sent 333more rapidly than one every 2 seconds. By default, any IPs returned 334as part of a DNS lookup are assumed to be for a single instance of 335<code>ntpd</code>, and therefore <code>sntp</code> will send queries to these IPs 336one after another, with a 2-second gap in between each query. 337 338 <p>The <span class="option">-c</span> or <span class="option">--concurrent</span> flag says that any IPs 339returned for the DNS lookup of the supplied host-name are on 340different machines, so we can send concurrent queries. 341<div class="node"> 342<p><hr> 343<a name="sntp-gap"></a>Next: <a rel="next" accesskey="n" href="#sntp-kod">sntp kod</a>, 344Previous: <a rel="previous" accesskey="p" href="#sntp-concurrent">sntp concurrent</a>, 345Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 346<br> 347</div> 348 349<h4 class="subsection">gap option (-g)</h4> 350 351<p><a name="index-sntp_002dgap-9"></a> 352This is the “the gap (in milliseconds) between time requests” option. 353This option takes a number argument <span class="file">milliseconds</span>. 354Since we're only going to use the first valid response we get and 355there is benefit to specifying a good number of servers to query, 356separate the queries we send out by the specified number of 357milliseconds. 358<div class="node"> 359<p><hr> 360<a name="sntp-kod"></a>Next: <a rel="next" accesskey="n" href="#sntp-keyfile">sntp keyfile</a>, 361Previous: <a rel="previous" accesskey="p" href="#sntp-gap">sntp gap</a>, 362Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 363<br> 364</div> 365 366<h4 class="subsection">kod option (-K)</h4> 367 368<p><a name="index-sntp_002dkod-10"></a> 369This is the “kod history filename” option. 370This option takes a file argument <span class="file">file-name</span>. 371Specifies the filename to be used for the persistent history of KoD 372responses received from servers. If the file does not exist, a 373warning message will be displayed. The file will not be created. 374<div class="node"> 375<p><hr> 376<a name="sntp-keyfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-logfile">sntp logfile</a>, 377Previous: <a rel="previous" accesskey="p" href="#sntp-kod">sntp kod</a>, 378Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 379<br> 380</div> 381 382<h4 class="subsection">keyfile option (-k)</h4> 383 384<p><a name="index-sntp_002dkeyfile-11"></a> 385This is the “look in this file for the key specified with <span class="option">-a</span>” option. 386This option takes a file argument <span class="file">file-name</span>. 387This option specifies the keyfile. 388<code>sntp</code> will search for the key specified with <span class="option">-a</span> 389<span class="file">keyno</span> in this file. See <span class="command">ntp.keys(5)</span> for more 390information. 391<div class="node"> 392<p><hr> 393<a name="sntp-logfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-steplimit">sntp steplimit</a>, 394Previous: <a rel="previous" accesskey="p" href="#sntp-keyfile">sntp keyfile</a>, 395Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 396<br> 397</div> 398 399<h4 class="subsection">logfile option (-l)</h4> 400 401<p><a name="index-sntp_002dlogfile-12"></a> 402This is the “log to specified logfile” option. 403This option takes a file argument <span class="file">file-name</span>. 404This option causes the client to write log messages to the specified 405<span class="file">logfile</span>. 406<div class="node"> 407<p><hr> 408<a name="sntp-steplimit"></a>Next: <a rel="next" accesskey="n" href="#sntp-ntpversion">sntp ntpversion</a>, 409Previous: <a rel="previous" accesskey="p" href="#sntp-logfile">sntp logfile</a>, 410Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 411<br> 412</div> 413 414<h4 class="subsection">steplimit option (-M)</h4> 415 416<p><a name="index-sntp_002dsteplimit-13"></a> 417This is the “adjustments less than <var>steplimit</var> msec will be slewed” option. 418This option takes a number argument. 419If the time adjustment is less than <span class="file">steplimit</span> milliseconds, 420slew the amount using <span class="command">adjtime(2)</span>. Otherwise, step the 421correction using <span class="command">settimeofday(2)</span>. The default value is 0, 422which means all adjustments will be stepped. This is a feature, as 423different situations demand different values. 424<div class="node"> 425<p><hr> 426<a name="sntp-ntpversion"></a>Next: <a rel="next" accesskey="n" href="#sntp-usereservedport">sntp usereservedport</a>, 427Previous: <a rel="previous" accesskey="p" href="#sntp-steplimit">sntp steplimit</a>, 428Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 429<br> 430</div> 431 432<h4 class="subsection">ntpversion option (-o)</h4> 433 434<p><a name="index-sntp_002dntpversion-14"></a> 435This is the “send <var>int</var> as our ntp protocol version” option. 436This option takes a number argument. 437When sending requests to a remote server, tell them we are running 438NTP protocol version <span class="file">ntpversion</span> . 439<div class="node"> 440<p><hr> 441<a name="sntp-usereservedport"></a>Next: <a rel="next" accesskey="n" href="#sntp-timeout">sntp timeout</a>, 442Previous: <a rel="previous" accesskey="p" href="#sntp-ntpversion">sntp ntpversion</a>, 443Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 444<br> 445</div> 446 447<h4 class="subsection">usereservedport option (-r)</h4> 448 449<p><a name="index-sntp_002dusereservedport-15"></a> 450This is the “use the ntp reserved port (port 123)” option. 451Use port 123, which is reserved for NTP, for our network 452communications. 453<div class="node"> 454<p><hr> 455<a name="sntp-timeout"></a>Next: <a rel="next" accesskey="n" href="#sntp-wait">sntp wait</a>, 456Previous: <a rel="previous" accesskey="p" href="#sntp-usereservedport">sntp usereservedport</a>, 457Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 458<br> 459</div> 460 461<h4 class="subsection">timeout option (-t)</h4> 462 463<p><a name="index-sntp_002dtimeout-16"></a> 464This is the “the number of seconds to wait for responses” option. 465This option takes a number argument <span class="file">seconds</span>. 466When waiting for a reply, <code>sntp</code> will wait the number 467of seconds specified before giving up. The default should be 468more than enough for a unicast response. If <code>sntp</code> is 469only waiting for a broadcast response a longer timeout is 470likely needed. 471<div class="node"> 472<p><hr> 473<a name="sntp-wait"></a>Next: <a rel="next" accesskey="n" href="#sntp-config">sntp config</a>, 474Previous: <a rel="previous" accesskey="p" href="#sntp-timeout">sntp timeout</a>, 475Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 476<br> 477</div> 478 479<h4 class="subsection">wait option</h4> 480 481<p><a name="index-sntp_002dwait-17"></a> 482This is the “wait for pending replies (if not setting the time)” option. 483 484<p class="noindent">This option has some usage constraints. It: 485 <ul> 486<li>can be disabled with –no-wait. 487<li>It is enabled by default. 488</ul> 489 490 <p>If we are not setting the time, wait for all pending responses. 491 492<div class="node"> 493<p><hr> 494<a name="sntp-config"></a>Next: <a rel="next" accesskey="n" href="#sntp-exit-status">sntp exit status</a>, 495Previous: <a rel="previous" accesskey="p" href="#sntp-wait">sntp wait</a>, 496Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 497<br> 498</div> 499 500<h4 class="subsection">presetting/configuring sntp</h4> 501 502<p>Any option that is not marked as <i>not presettable</i> may be preset by 503loading values from configuration ("rc" or "ini") files, and values from environment variables named <code>SNTP</code> and <code>SNTP_<OPTION_NAME></code>. <code><OPTION_NAME></code> must be one of 504the options listed above in upper case and segmented with underscores. 505The <code>SNTP</code> variable will be tokenized and parsed like 506the command line. The remaining variables are tested for existence and their 507values are treated like option arguments. 508 509<p class="noindent"><code>libopts</code> will search in 2 places for configuration files: 510 <ul> 511<li>$HOME 512<li>$PWD 513</ul> 514 The environment variables <code>HOME</code>, and <code>PWD</code> 515are expanded and replaced when <span class="file">sntp</span> runs. 516For any of these that are plain files, they are simply processed. 517For any that are directories, then a file named <span class="file">.ntprc</span> is searched for 518within that directory and processed. 519 520 <p>Configuration files may be in a wide variety of formats. 521The basic format is an option name followed by a value (argument) on the 522same line. Values may be separated from the option name with a colon, 523equal sign or simply white space. Values may be continued across multiple 524lines by escaping the newline with a backslash. 525 526 <p>Multiple programs may also share the same initialization file. 527Common options are collected at the top, followed by program specific 528segments. The segments are separated by lines like: 529<pre class="example"> [SNTP] 530</pre> 531 <p class="noindent">or by 532<pre class="example"> <?program sntp> 533</pre> 534 <p class="noindent">Do not mix these styles within one configuration file. 535 536 <p>Compound values and carefully constructed string values may also be 537specified using XML syntax: 538<pre class="example"> <option-name> 539 <sub-opt>...&lt;...&gt;...</sub-opt> 540 </option-name> 541</pre> 542 <p class="noindent">yielding an <code>option-name.sub-opt</code> string value of 543<pre class="example"> "...<...>..." 544</pre> 545 <p><code>AutoOpts</code> does not track suboptions. You simply note that it is a 546hierarchicly valued option. <code>AutoOpts</code> does provide a means for searching 547the associated name/value pair list (see: optionFindValue). 548 549 <p>The command line options relating to configuration and/or usage help are: 550 551<h5 class="subsubheading">version (-)</h5> 552 553<p>Print the program version to standard out, optionally with licensing 554information, then exit 0. The optional argument specifies how much licensing 555detail to provide. The default is to print just the version. The licensing infomation may be selected with an option argument. 556Only the first letter of the argument is examined: 557 558 <dl> 559<dt><span class="samp">version</span><dd>Only print the version. This is the default. 560<br><dt><span class="samp">copyright</span><dd>Name the copyright usage licensing terms. 561<br><dt><span class="samp">verbose</span><dd>Print the full copyright usage licensing terms. 562</dl> 563 564<div class="node"> 565<p><hr> 566<a name="sntp-exit-status"></a>Next: <a rel="next" accesskey="n" href="#sntp-Usage">sntp Usage</a>, 567Previous: <a rel="previous" accesskey="p" href="#sntp-config">sntp config</a>, 568Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 569<br> 570</div> 571 572<h4 class="subsection">sntp exit status</h4> 573 574<p>One of the following exit values will be returned: 575 <dl> 576<dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution. 577<br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid. 578<br><dt><span class="samp">66 (EX_NOINPUT)</span><dd>A specified configuration file could not be loaded. 579<br><dt><span class="samp">70 (EX_SOFTWARE)</span><dd>libopts had an internal operational error. Please report 580it to autogen-users@lists.sourceforge.net. Thank you. 581</dl> 582 <div class="node"> 583<p><hr> 584<a name="sntp-Usage"></a>Next: <a rel="next" accesskey="n" href="#sntp-Authors">sntp Authors</a>, 585Previous: <a rel="previous" accesskey="p" href="#sntp-exit-status">sntp exit status</a>, 586Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 587<br> 588</div> 589 590<h4 class="subsection">sntp Usage</h4> 591 592<div class="node"> 593<p><hr> 594<a name="sntp-Authors"></a>Previous: <a rel="previous" accesskey="p" href="#sntp-Usage">sntp Usage</a>, 595Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 596<br> 597</div> 598 599<h4 class="subsection">sntp Authors</h4> 600 601<div class="node"> 602<p><hr> 603<a name="Usage"></a> 604<br> 605</div> 606 607<!-- node-name, next, previous, up --> 608<h3 class="section">Usage</h3> 609 610<p>The simplest use of this program is as an unprivileged command to 611check the current time, offset, and error in the local clock. 612For example: 613 614<pre class="example"> sntp ntpserver.somewhere 615</pre> 616 <p>With suitable privilege, it can be run as a command or in a 617<code>crom</code> job to reset the local clock from a reliable server, like 618the <code>ntpdate</code> and <code>rdate</code> commands. 619For example: 620 621<pre class="example"> sntp -a ntpserver.somewhere 622</pre> 623 </body></html> 624 625