220 lines
7.0 KiB
Groff
220 lines
7.0 KiB
Groff
.TH SNTP 1 2011-12-24 "( 4.2.6p5)" "Programmer's Manual"
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.\" EDIT THIS FILE WITH CAUTION (sntp.1)
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.\"
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.\" It has been AutoGen-ed December 24, 2011 at 06:33:59 PM by AutoGen 5.12
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.\" From the definitions sntp-opts.def
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.\" and the template file agman1.tpl
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.\"
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.SH NAME
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sntp \- standard Simple Network Time Protocol program
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.SH SYNOPSIS
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.B sntp
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.\" Mixture of short (flag) options and long options
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.RB [ \-\fIflag\fP " [\fIvalue\fP]]... [" \--\fIopt-name\fP " [[=| ]\fIvalue\fP]]..."
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.br
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.in +8
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[ hostname-or-IP ...]
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.PP
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.SH "DESCRIPTION"
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This manual page briefly documents the \fBsntp\fP command.
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.I sntp
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can be used as a SNTP client to query a NTP or SNTP server and either display
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the time or set the local system's time (given suitable privilege). It can be
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run as an interactive command or in a
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.I cron
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job.
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NTP (the Network Time Protocol) and SNTP (the Simple Network Time Protocol)
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are defined and described by RFC 5905.
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.PP
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The default is to write the estimated correct local date and time (i.e. not
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UTC) to the standard output in a format like
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.BR "'1996-10-15 20:17:25.123 (+0800) +4.567 +/- 0.089 secs'" ,
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where the
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.B "'(+0800)'"
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means that to get to UTC from the reported local time one must
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add 8 hours and 0 minutes,
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and the
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.B "'+4.567 +/- 0.089 secs'"
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indicates the local clock is 4.567 seconds behind the correct time
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(so 4.567 seconds must be added to the local clock to get it to be correct),
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and the time of
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'1996-10-15 20:17:25.123'
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is believed to be correct to within
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+/- 0.089
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seconds.
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.SH OPTIONS
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.TP
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.BR \-4 ", " \--ipv4
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Force IPv4 DNS name resolution.
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This option must not appear in combination with any of the following options:
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ipv6.
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.sp
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Force DNS resolution of the following host names on the command line
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to the IPv4 namespace.
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.TP
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.BR \-6 ", " \--ipv6
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Force IPv6 DNS name resolution.
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This option must not appear in combination with any of the following options:
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ipv4.
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.sp
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Force DNS resolution of the following host names on the command line
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to the IPv6 namespace.
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.TP
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.BR \-d ", " \--normalverbose
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Normal verbose.
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.sp
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Diagnostic messages for non-fatal errors and a limited amount of
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tracing should be written to standard error. Fatal ones always
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produce a diagnostic. This option should be set when there is a
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suspected problem with the server, network or the source.
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.TP
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.BR \-K " \fIfile-name\fP, " \--kod "=" \fIfile-name\fP
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KoD history filename.
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.sp
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Specifies the filename to be used to persist the history of KoD
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responses received from servers. The default is
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/var/db/ntp-kod.
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.TP
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.BR \-p ", " \--syslog
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Logging with syslog.
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This option must not appear in combination with any of the following options:
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logfile.
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.sp
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When this option is set all logging will be done using syslog.
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.TP
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.BR \-l " \fIfile-name\fP, " \--logfile "=" \fIfile-name\fP
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Log to specified logfile.
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This option must not appear in combination with any of the following options:
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syslog.
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.sp
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This option causes the client to write log messages to the specified
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logfile.
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.TP
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.BR \-s ", " \--settod
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Set (step) the time with settimeofday().
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This option must not appear in combination with any of the following options:
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adjtime.
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.sp
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.TP
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.BR \-j ", " \--adjtime
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Set (slew) the time with adjtime().
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This option must not appear in combination with any of the following options:
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settod.
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.sp
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.TP
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.BR \-b " \fIbroadcast-address\fP, " \--broadcast "=" \fIbroadcast-address\fP
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Use broadcasts to the address specified for synchronisation.
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.sp
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If specified SNTP will listen to the specified broadcast address
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for NTP broadcasts. The default maximum wait time,
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68 seconds, can be modified with \-t.
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.TP
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.BR \-t " \fIseconds\fP, " \--timeout "=" \fIseconds\fP
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Specify the number of seconds to wait for broadcasts.
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This option takes an integer number as its argument.
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The default \fIseconds\fP for this option is:
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.ti +4
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68
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.sp
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When waiting for a broadcast packet SNTP will wait the number
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of seconds specified before giving up. Default 68 seconds.
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.TP
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.BR \-a " \fIauth-keynumber\fP, " \--authentication "=" \fIauth-keynumber\fP
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Enable authentication with the key auth-keynumber.
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This option takes an integer number as its argument.
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.sp
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This option enables authentication using the key specified in this option's argument.
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The argument of this option is the keyid, a number specified in the keyfile as this
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key's identifier. See the keyfile option (-k) for more details.
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.TP
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.BR \-k " \fIfile-name\fP, " \--keyfile "=" \fIfile-name\fP
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Specify a keyfile. SNTP will look in this file for the key specified with \-a.
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.sp
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This option specifies the keyfile. SNTP will search for the key specified with \-a keyno in this
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file. Key files follow the following format:
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keyid keytype key
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Where keyid is a number identifying this key
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keytype is one of the follow:
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S Key in 64 Bit hexadecimal number as specified in in the DES specification.
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N Key in 64 Bit hexadecimal number as specified in the NTP standard.
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A Key in a 1-to-8 character ASCII string.
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M Key in a 1-to-8 character ASCII string using the MD5 authentication scheme.
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For more information see ntp.keys(5).
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.TP
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.BR \-? , " \--help"
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Display extended usage information and exit.
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.TP
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.BR \-! , " \--more-help"
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Extended usage information passed thru pager.
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.TP
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.BR \-> " [\fIrcfile\fP]," " \--save-opts" "[=\fIrcfile\fP]"
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Save the option state to \fIrcfile\fP. The default is the \fIlast\fP
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configuration file listed in the \fBOPTION PRESETS\fP section, below.
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.TP
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.BR \-< " \fIrcfile\fP," " \--load-opts" "=\fIrcfile\fP," " \--no-load-opts"
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Load options from \fIrcfile\fP.
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The \fIno-load-opts\fP form will disable the loading
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of earlier RC/INI files. \fI--no-load-opts\fP is handled early,
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out of order.
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.TP
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.BR \- " [{\fIv|c|n\fP}]," " \--version" "[=\fI{v|c|n}\fP]"
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Output version of program and exit. The default mode is `v', a simple
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version. The `c' mode will print copyright information and `n' will
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print the full copyright notice.
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.SH OPTION PRESETS
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Any option that is not marked as \fInot presettable\fP may be preset
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by loading values from configuration ("RC" or ".INI") file(s) and values from
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environment variables named:
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.nf
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\fBSNTP_<option-name>\fP or \fBSNTP\fP
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.fi
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.ad
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The environmental presets take precedence (are processed later than)
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the configuration files.
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The \fIhomerc\fP files are "\fI$HOME\fP", and "\fI.\fP".
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If any of these are directories, then the file \fI.ntprc\fP
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is searched for within those directories.
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.SH USAGE
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The simplest use of this program is as an unprivileged command to check the
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current time and error in the local clock. For example:
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.IP
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.B sntp ntpserver.somewhere
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.PP
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With suitable privilege, it can be run as a command or in a
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.I cron
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job to reset the local clock from a reliable server, like the
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.I ntpdate
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and
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.I rdate
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commands. For example:
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.IP
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.B sntp \-a ntpserver.somewhere
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.SH RETURN VALUE
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The program returns a zero exit
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status for success, and a non-zero one otherwise.
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.SH BUGS
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Please report bugs to http://bugs.ntp.org .
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.SH AUTHOR
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David L. Mills and/or others
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.br
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Please send bug reports to: http://bugs.ntp.org, bugs@ntp.org
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.PP
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.nf
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.na
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see html/copyright.html
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.fi
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.ad
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.PP
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This manual page was \fIAutoGen\fP-erated from the \fBsntp\fP
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option definitions.
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