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 4.2.8p11 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. 4.2.7p245 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 these options: 185 ipv6 186 -6 no ipv6 Force IPv6 DNS name resolution 187 - prohibits these options: 188 ipv4 189 -a Num authentication Enable authentication with the key @var{auth-keynumber} 190 -B Num bctimeout The number of seconds to wait for broadcasts 191 -b Str broadcast Listen to the address specified for broadcast time sync 192 - may appear multiple times 193 -c Str concurrent Concurrently query all IPs returned for host-name 194 - may appear multiple times 195 -d no debug-level Increase debug verbosity level 196 - may appear multiple times 197 -D Str set-debug-level Set the debug verbosity level 198 - may appear multiple times 199 -g Num gap The gap (in milliseconds) between time requests 200 -K Fil kod KoD history filename 201 -k Fil keyfile Look in this file for the key specified with @option{-a} 202 -l Fil logfile Log to specified logfile 203 -M Num steplimit Adjustments less than @var{steplimit} msec will be slewed 204 - It must be in the range: 205 greater than or equal to 0 206 -o Num ntpversion Send @var{int} as our NTP version 207 - It must be in the range: 208 0 to 7 209 -r no usereservedport Use the NTP Reserved Port (port 123) 210 -S no step OK to 'step' the time with @command{settimeofday(2)} 211 -s no slew OK to 'slew' the time with @command{adjtime(2)} 212 -u Num uctimeout The number of seconds to wait for unicast responses 213 no wait Wait for pending replies (if not setting the time) 214 - disabled as --no-wait 215 - enabled by default 216 opt version Output version information and exit 217 -? no help Display extended usage information and exit 218 -! no more-help Extended usage information passed thru pager 219 -> opt save-opts Save the option state to a config file 220 -< Str load-opts Load options from a config file 221 - disabled as --no-load-opts 222 - may appear multiple times 223 224Options are specified by doubled hyphens and their name or by a single 225hyphen and the flag character. 226 227 228 229The following option preset mechanisms are supported: 230 - reading file $HOME/.ntprc 231 - reading file ./.ntprc 232 - examining environment variables named SNTP_* 233 234please send bug reports to: http://bugs.ntp.org, bugs@ntp.org 235</pre> 236 <div class="node"> 237<p><hr> 238<a name="sntp-ipv4"></a>Next: <a rel="next" accesskey="n" href="#sntp-ipv6">sntp ipv6</a>, 239Previous: <a rel="previous" accesskey="p" href="#sntp-usage">sntp usage</a>, 240Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 241<br> 242</div> 243 244<h4 class="subsection">ipv4 option (-4)</h4> 245 246<p><a name="index-sntp_002dipv4-4"></a> 247This is the “force ipv4 dns name resolution” option. 248 249<p class="noindent">This option has some usage constraints. It: 250 <ul> 251<li>must not appear in combination with any of the following options: 252ipv6. 253</ul> 254 255 <p>Force DNS resolution of the following host names on the command line 256to the IPv4 namespace. 257<div class="node"> 258<p><hr> 259<a name="sntp-ipv6"></a>Next: <a rel="next" accesskey="n" href="#sntp-authentication">sntp authentication</a>, 260Previous: <a rel="previous" accesskey="p" href="#sntp-ipv4">sntp ipv4</a>, 261Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 262<br> 263</div> 264 265<h4 class="subsection">ipv6 option (-6)</h4> 266 267<p><a name="index-sntp_002dipv6-5"></a> 268This is the “force ipv6 dns name resolution” option. 269 270<p class="noindent">This option has some usage constraints. It: 271 <ul> 272<li>must not appear in combination with any of the following options: 273ipv4. 274</ul> 275 276 <p>Force DNS resolution of the following host names on the command line 277to the IPv6 namespace. 278<div class="node"> 279<p><hr> 280<a name="sntp-authentication"></a>Next: <a rel="next" accesskey="n" href="#sntp-broadcast">sntp broadcast</a>, 281Previous: <a rel="previous" accesskey="p" href="#sntp-ipv6">sntp ipv6</a>, 282Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 283<br> 284</div> 285 286<h4 class="subsection">authentication option (-a)</h4> 287 288<p><a name="index-sntp_002dauthentication-6"></a> 289This is the “enable authentication with the key <var>auth-keynumber</var>” option. 290This option takes a number argument <span class="file">auth-keynumber</span>. 291Enable authentication using the key specified in this option's 292argument. The argument of this option is the <span class="option">keyid</span>, a 293number specified in the <span class="option">keyfile</span> as this key's identifier. 294See the <span class="option">keyfile</span> option (<span class="option">-k</span>) for more details. 295<div class="node"> 296<p><hr> 297<a name="sntp-broadcast"></a>Next: <a rel="next" accesskey="n" href="#sntp-concurrent">sntp concurrent</a>, 298Previous: <a rel="previous" accesskey="p" href="#sntp-authentication">sntp authentication</a>, 299Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 300<br> 301</div> 302 303<h4 class="subsection">broadcast option (-b)</h4> 304 305<p><a name="index-sntp_002dbroadcast-7"></a> 306This is the “listen to the address specified for broadcast time sync” option. 307This option takes a string argument <span class="file">broadcast-address</span>. 308 309<p class="noindent">This option has some usage constraints. It: 310 <ul> 311<li>may appear an unlimited number of times. 312</ul> 313 314 <p>If specified <code>sntp</code> will listen to the specified address 315for NTP broadcasts. The default maximum wait time 316can (and probably should) be modified with <span class="option">-t</span>. 317<div class="node"> 318<p><hr> 319<a name="sntp-concurrent"></a>Next: <a rel="next" accesskey="n" href="#sntp-gap">sntp gap</a>, 320Previous: <a rel="previous" accesskey="p" href="#sntp-broadcast">sntp broadcast</a>, 321Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 322<br> 323</div> 324 325<h4 class="subsection">concurrent option (-c)</h4> 326 327<p><a name="index-sntp_002dconcurrent-8"></a> 328This is the “concurrently query all ips returned for host-name” option. 329This option takes a string argument <span class="file">host-name</span>. 330 331<p class="noindent">This option has some usage constraints. It: 332 <ul> 333<li>may appear an unlimited number of times. 334</ul> 335 336 <p>Requests from an NTP "client" to a "server" should never be sent 337more rapidly than one every 2 seconds. By default, any IPs returned 338as part of a DNS lookup are assumed to be for a single instance of 339<code>ntpd</code>, and therefore <code>sntp</code> will send queries to these IPs 340one after another, with a 2-second gap in between each query. 341 342 <p>The <span class="option">-c</span> or <span class="option">--concurrent</span> flag says that any IPs 343returned for the DNS lookup of the supplied host-name are on 344different machines, so we can send concurrent queries. 345<div class="node"> 346<p><hr> 347<a name="sntp-gap"></a>Next: <a rel="next" accesskey="n" href="#sntp-kod">sntp kod</a>, 348Previous: <a rel="previous" accesskey="p" href="#sntp-concurrent">sntp concurrent</a>, 349Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 350<br> 351</div> 352 353<h4 class="subsection">gap option (-g)</h4> 354 355<p><a name="index-sntp_002dgap-9"></a> 356This is the “the gap (in milliseconds) between time requests” option. 357This option takes a number argument <span class="file">milliseconds</span>. 358Since we're only going to use the first valid response we get and 359there is benefit to specifying a good number of servers to query, 360separate the queries we send out by the specified number of 361milliseconds. 362<div class="node"> 363<p><hr> 364<a name="sntp-kod"></a>Next: <a rel="next" accesskey="n" href="#sntp-keyfile">sntp keyfile</a>, 365Previous: <a rel="previous" accesskey="p" href="#sntp-gap">sntp gap</a>, 366Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 367<br> 368</div> 369 370<h4 class="subsection">kod option (-K)</h4> 371 372<p><a name="index-sntp_002dkod-10"></a> 373This is the “kod history filename” option. 374This option takes a file argument <span class="file">file-name</span>. 375Specifies the filename to be used for the persistent history of KoD 376responses received from servers. If the file does not exist, a 377warning message will be displayed. The file will not be created. 378<div class="node"> 379<p><hr> 380<a name="sntp-keyfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-logfile">sntp logfile</a>, 381Previous: <a rel="previous" accesskey="p" href="#sntp-kod">sntp kod</a>, 382Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 383<br> 384</div> 385 386<h4 class="subsection">keyfile option (-k)</h4> 387 388<p><a name="index-sntp_002dkeyfile-11"></a> 389This is the “look in this file for the key specified with <span class="option">-a</span>” option. 390This option takes a file argument <span class="file">file-name</span>. 391This option specifies the keyfile. 392<code>sntp</code> will search for the key specified with <span class="option">-a</span> 393<span class="file">keyno</span> in this file. See <span class="command">ntp.keys(5)</span> for more 394information. 395<div class="node"> 396<p><hr> 397<a name="sntp-logfile"></a>Next: <a rel="next" accesskey="n" href="#sntp-steplimit">sntp steplimit</a>, 398Previous: <a rel="previous" accesskey="p" href="#sntp-keyfile">sntp keyfile</a>, 399Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 400<br> 401</div> 402 403<h4 class="subsection">logfile option (-l)</h4> 404 405<p><a name="index-sntp_002dlogfile-12"></a> 406This is the “log to specified logfile” option. 407This option takes a file argument <span class="file">file-name</span>. 408This option causes the client to write log messages to the specified 409<span class="file">logfile</span>. 410<div class="node"> 411<p><hr> 412<a name="sntp-steplimit"></a>Next: <a rel="next" accesskey="n" href="#sntp-ntpversion">sntp ntpversion</a>, 413Previous: <a rel="previous" accesskey="p" href="#sntp-logfile">sntp logfile</a>, 414Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 415<br> 416</div> 417 418<h4 class="subsection">steplimit option (-M)</h4> 419 420<p><a name="index-sntp_002dsteplimit-13"></a> 421This is the “adjustments less than <var>steplimit</var> msec will be slewed” option. 422This option takes a number argument. 423If the time adjustment is less than <span class="file">steplimit</span> milliseconds, 424slew the amount using <span class="command">adjtime(2)</span>. Otherwise, step the 425correction using <span class="command">settimeofday(2)</span>. The default value is 0, 426which means all adjustments will be stepped. This is a feature, as 427different situations demand different values. 428<div class="node"> 429<p><hr> 430<a name="sntp-ntpversion"></a>Next: <a rel="next" accesskey="n" href="#sntp-usereservedport">sntp usereservedport</a>, 431Previous: <a rel="previous" accesskey="p" href="#sntp-steplimit">sntp steplimit</a>, 432Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 433<br> 434</div> 435 436<h4 class="subsection">ntpversion option (-o)</h4> 437 438<p><a name="index-sntp_002dntpversion-14"></a> 439This is the “send <var>int</var> as our ntp protocol version” option. 440This option takes a number argument. 441When sending requests to a remote server, tell them we are running 442NTP protocol version <span class="file">ntpversion</span> . 443<div class="node"> 444<p><hr> 445<a name="sntp-usereservedport"></a>Next: <a rel="next" accesskey="n" href="#sntp-timeout">sntp timeout</a>, 446Previous: <a rel="previous" accesskey="p" href="#sntp-ntpversion">sntp ntpversion</a>, 447Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 448<br> 449</div> 450 451<h4 class="subsection">usereservedport option (-r)</h4> 452 453<p><a name="index-sntp_002dusereservedport-15"></a> 454This is the “use the ntp reserved port (port 123)” option. 455Use port 123, which is reserved for NTP, for our network 456communications. 457<div class="node"> 458<p><hr> 459<a name="sntp-timeout"></a>Next: <a rel="next" accesskey="n" href="#sntp-wait">sntp wait</a>, 460Previous: <a rel="previous" accesskey="p" href="#sntp-usereservedport">sntp usereservedport</a>, 461Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 462<br> 463</div> 464 465<h4 class="subsection">timeout option (-t)</h4> 466 467<p><a name="index-sntp_002dtimeout-16"></a> 468This is the “the number of seconds to wait for responses” option. 469This option takes a number argument <span class="file">seconds</span>. 470When waiting for a reply, <code>sntp</code> will wait the number 471of seconds specified before giving up. The default should be 472more than enough for a unicast response. If <code>sntp</code> is 473only waiting for a broadcast response a longer timeout is 474likely needed. 475<div class="node"> 476<p><hr> 477<a name="sntp-wait"></a>Next: <a rel="next" accesskey="n" href="#sntp-config">sntp config</a>, 478Previous: <a rel="previous" accesskey="p" href="#sntp-timeout">sntp timeout</a>, 479Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 480<br> 481</div> 482 483<h4 class="subsection">wait option</h4> 484 485<p><a name="index-sntp_002dwait-17"></a> 486This is the “wait for pending replies (if not setting the time)” option. 487 488<p class="noindent">This option has some usage constraints. It: 489 <ul> 490<li>can be disabled with –no-wait. 491<li>It is enabled by default. 492</ul> 493 494 <p>If we are not setting the time, wait for all pending responses. 495 496<div class="node"> 497<p><hr> 498<a name="sntp-config"></a>Next: <a rel="next" accesskey="n" href="#sntp-exit-status">sntp exit status</a>, 499Previous: <a rel="previous" accesskey="p" href="#sntp-wait">sntp wait</a>, 500Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 501<br> 502</div> 503 504<h4 class="subsection">presetting/configuring sntp</h4> 505 506<p>Any option that is not marked as <i>not presettable</i> may be preset by 507loading 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 508the options listed above in upper case and segmented with underscores. 509The <code>SNTP</code> variable will be tokenized and parsed like 510the command line. The remaining variables are tested for existence and their 511values are treated like option arguments. 512 513<p class="noindent"><code>libopts</code> will search in 2 places for configuration files: 514 <ul> 515<li>$HOME 516<li>$PWD 517</ul> 518 The environment variables <code>HOME</code>, and <code>PWD</code> 519are expanded and replaced when <span class="file">sntp</span> runs. 520For any of these that are plain files, they are simply processed. 521For any that are directories, then a file named <span class="file">.ntprc</span> is searched for 522within that directory and processed. 523 524 <p>Configuration files may be in a wide variety of formats. 525The basic format is an option name followed by a value (argument) on the 526same line. Values may be separated from the option name with a colon, 527equal sign or simply white space. Values may be continued across multiple 528lines by escaping the newline with a backslash. 529 530 <p>Multiple programs may also share the same initialization file. 531Common options are collected at the top, followed by program specific 532segments. The segments are separated by lines like: 533<pre class="example"> [SNTP] 534</pre> 535 <p class="noindent">or by 536<pre class="example"> <?program sntp> 537</pre> 538 <p class="noindent">Do not mix these styles within one configuration file. 539 540 <p>Compound values and carefully constructed string values may also be 541specified using XML syntax: 542<pre class="example"> <option-name> 543 <sub-opt>...&lt;...&gt;...</sub-opt> 544 </option-name> 545</pre> 546 <p class="noindent">yielding an <code>option-name.sub-opt</code> string value of 547<pre class="example"> "...<...>..." 548</pre> 549 <p><code>AutoOpts</code> does not track suboptions. You simply note that it is a 550hierarchicly valued option. <code>AutoOpts</code> does provide a means for searching 551the associated name/value pair list (see: optionFindValue). 552 553 <p>The command line options relating to configuration and/or usage help are: 554 555<h5 class="subsubheading">version (-)</h5> 556 557<p>Print the program version to standard out, optionally with licensing 558information, then exit 0. The optional argument specifies how much licensing 559detail to provide. The default is to print just the version. The licensing infomation may be selected with an option argument. 560Only the first letter of the argument is examined: 561 562 <dl> 563<dt><span class="samp">version</span><dd>Only print the version. This is the default. 564<br><dt><span class="samp">copyright</span><dd>Name the copyright usage licensing terms. 565<br><dt><span class="samp">verbose</span><dd>Print the full copyright usage licensing terms. 566</dl> 567 568<div class="node"> 569<p><hr> 570<a name="sntp-exit-status"></a>Next: <a rel="next" accesskey="n" href="#sntp-Usage">sntp Usage</a>, 571Previous: <a rel="previous" accesskey="p" href="#sntp-config">sntp config</a>, 572Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 573<br> 574</div> 575 576<h4 class="subsection">sntp exit status</h4> 577 578<p>One of the following exit values will be returned: 579 <dl> 580<dt><span class="samp">0 (EXIT_SUCCESS)</span><dd>Successful program execution. 581<br><dt><span class="samp">1 (EXIT_FAILURE)</span><dd>The operation failed or the command syntax was not valid. 582<br><dt><span class="samp">66 (EX_NOINPUT)</span><dd>A specified configuration file could not be loaded. 583<br><dt><span class="samp">70 (EX_SOFTWARE)</span><dd>libopts had an internal operational error. Please report 584it to autogen-users@lists.sourceforge.net. Thank you. 585</dl> 586 <div class="node"> 587<p><hr> 588<a name="sntp-Usage"></a>Next: <a rel="next" accesskey="n" href="#sntp-Authors">sntp Authors</a>, 589Previous: <a rel="previous" accesskey="p" href="#sntp-exit-status">sntp exit status</a>, 590Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 591<br> 592</div> 593 594<h4 class="subsection">sntp Usage</h4> 595 596<div class="node"> 597<p><hr> 598<a name="sntp-Authors"></a>Previous: <a rel="previous" accesskey="p" href="#sntp-Usage">sntp Usage</a>, 599Up: <a rel="up" accesskey="u" href="#sntp-Invocation">sntp Invocation</a> 600<br> 601</div> 602 603<h4 class="subsection">sntp Authors</h4> 604 605<div class="node"> 606<p><hr> 607<a name="Usage"></a> 608<br> 609</div> 610 611<!-- node-name, next, previous, up --> 612<h3 class="section">Usage</h3> 613 614<p>The simplest use of this program is as an unprivileged command to 615check the current time, offset, and error in the local clock. 616For example: 617 618<pre class="example"> sntp ntpserver.somewhere 619</pre> 620 <p>With suitable privilege, it can be run as a command or in a 621<code>crom</code> job to reset the local clock from a reliable server, like 622the <code>ntpdate</code> and <code>rdate</code> commands. 623For example: 624 625<pre class="example"> sntp -a ntpserver.somewhere 626</pre> 627 </body></html> 628 629