437 lines
9.9 KiB
Groff
437 lines
9.9 KiB
Groff
.TH ZIC 8
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.SH NAME
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zic \- time zone compiler
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.SH SYNOPSIS
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.B zic
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[
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.B \-\-version
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]
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[
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.B \-v
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] [
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.B \-d
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.I directory
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] [
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.B \-l
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.I localtime
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] [
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.B \-p
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.I posixrules
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] [
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.B \-L
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.I leapsecondfilename
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] [
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.B \-s
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] [
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.B \-y
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.I command
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] [
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.I filename
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\&... ]
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.SH DESCRIPTION
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.if t .ds lq ``
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.if t .ds rq ''
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.if n .ds lq \&"\"
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.if n .ds rq \&"\"
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.de q
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\\$3\*(lq\\$1\*(rq\\$2
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..
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.I Zic
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reads text from the file(s) named on the command line
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and creates the time conversion information files specified in this input.
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If a
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.I filename
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is
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.BR \- ,
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the standard input is read.
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.PP
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These options are available:
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.TP
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.BI "\-\-version"
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Output version information and exit.
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.TP
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.BI "\-d " directory
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Create time conversion information files in the named directory rather than
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in the standard directory named below.
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.TP
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.BI "\-l " timezone
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Use the given time zone as local time.
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.I Zic
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will act as if the input contained a link line of the form
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.sp
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.ti +.5i
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Link \fItimezone\fP localtime
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.TP
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.BI "\-p " timezone
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Use the given time zone's rules when handling POSIX-format
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time zone environment variables.
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.I Zic
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will act as if the input contained a link line of the form
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.sp
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.ti +.5i
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Link \fItimezone\fP posixrules
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.TP
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.BI "\-L " leapsecondfilename
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Read leap second information from the file with the given name.
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If this option is not used,
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no leap second information appears in output files.
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.TP
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.B \-v
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Complain if a year that appears in a data file is outside the range
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of years representable by
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.IR time (2)
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values.
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Also complain if a time of 24:00
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(which cannot be handled by pre-1998 versions of
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.IR zic )
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appears in the input.
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.TP
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.B \-s
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Limit time values stored in output files to values that are the same
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whether they're taken to be signed or unsigned.
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You can use this option to generate SVVS-compatible files.
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.TP
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.BI "\-y " command
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Use the given
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.I command
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rather than
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.B yearistype
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when checking year types (see below).
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.PP
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Input lines are made up of fields.
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Fields are separated from one another by any number of white space characters.
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Leading and trailing white space on input lines is ignored.
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An unquoted sharp character (#) in the input introduces a comment which extends
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to the end of the line the sharp character appears on.
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White space characters and sharp characters may be enclosed in double quotes
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(") if they're to be used as part of a field.
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Any line that is blank (after comment stripping) is ignored.
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Non-blank lines are expected to be of one of three types:
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rule lines, zone lines, and link lines.
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.PP
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A rule line has the form
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.nf
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.ti +.5i
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.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
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.sp
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Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
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.sp
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For example:
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.ti +.5i
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.sp
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Rule US 1967 1973 \- Apr lastSun 2:00 1:00 D
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.sp
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.fi
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The fields that make up a rule line are:
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.TP "\w'LETTER/S'u"
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.B NAME
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Gives the (arbitrary) name of the set of rules this rule is part of.
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.TP
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.B FROM
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Gives the first year in which the rule applies.
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Any integer year can be supplied; the Gregorian calendar is assumed.
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The word
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.B minimum
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(or an abbreviation) means the minimum year representable as an integer.
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The word
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.B maximum
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(or an abbreviation) means the maximum year representable as an integer.
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Rules can describe times that are not representable as time values,
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with the unrepresentable times ignored; this allows rules to be portable
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among hosts with differing time value types.
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.TP
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.B TO
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Gives the final year in which the rule applies.
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In addition to
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.B minimum
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and
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.B maximum
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(as above),
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the word
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.B only
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(or an abbreviation)
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may be used to repeat the value of the
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.B FROM
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field.
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.TP
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.B TYPE
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Gives the type of year in which the rule applies.
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If
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.B TYPE
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is
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.B \-
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then the rule applies in all years between
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.B FROM
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and
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.B TO
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inclusive.
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If
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.B TYPE
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is something else, then
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.I zic
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executes the command
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.ti +.5i
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\fByearistype\fP \fIyear\fP \fItype\fP
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.br
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to check the type of a year:
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an exit status of zero is taken to mean that the year is of the given type;
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an exit status of one is taken to mean that the year is not of the given type.
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.TP
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.B IN
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Names the month in which the rule takes effect.
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Month names may be abbreviated.
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.TP
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.B ON
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Gives the day on which the rule takes effect.
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Recognized forms include:
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.nf
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.in +.5i
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.sp
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.ta \w'Sun<=25\0\0'u
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5 the fifth of the month
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lastSun the last Sunday in the month
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lastMon the last Monday in the month
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Sun>=8 first Sunday on or after the eighth
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Sun<=25 last Sunday on or before the 25th
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.fi
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.in -.5i
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.sp
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Names of days of the week may be abbreviated or spelled out in full.
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Note that there must be no spaces within the
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.B ON
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field.
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.TP
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.B AT
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Gives the time of day at which the rule takes effect.
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Recognized forms include:
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.nf
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.in +.5i
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.sp
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.ta \w'1:28:13\0\0'u
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2 time in hours
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2:00 time in hours and minutes
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15:00 24-hour format time (for times after noon)
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1:28:14 time in hours, minutes, and seconds
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\- equivalent to 0
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.fi
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.in -.5i
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.sp
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where hour 0 is midnight at the start of the day,
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and hour 24 is midnight at the end of the day.
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Any of these forms may be followed by the letter
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.B w
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if the given time is local
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.q "wall clock"
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time,
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.B s
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if the given time is local
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.q standard
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time, or
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.B u
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(or
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.B g
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or
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.BR z )
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if the given time is universal time;
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in the absence of an indicator,
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wall clock time is assumed.
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.TP
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.B SAVE
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Gives the amount of time to be added to local standard time when the rule is in
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effect.
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This field has the same format as the
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.B AT
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field
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(although, of course, the
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.B w
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and
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.B s
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suffixes are not used).
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.TP
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.B LETTER/S
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Gives the
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.q "variable part"
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(for example, the
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.q S
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or
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.q D
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in
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.q EST
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or
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.q EDT )
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of time zone abbreviations to be used when this rule is in effect.
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If this field is
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.BR \- ,
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the variable part is null.
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.PP
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A zone line has the form
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.sp
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.nf
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.ti +.5i
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.ta \w'Zone\0\0'u +\w'Australia/Adelaide\0\0'u +\w'GMTOFF\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u
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Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL]
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.sp
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For example:
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.sp
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.ti +.5i
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Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00
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.sp
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.fi
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The fields that make up a zone line are:
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.TP "\w'GMTOFF'u"
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.B NAME
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The name of the time zone.
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This is the name used in creating the time conversion information file for the
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zone.
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.TP
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.B GMTOFF
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The amount of time to add to UTC to get standard time in this zone.
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This field has the same format as the
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.B AT
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and
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.B SAVE
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fields of rule lines;
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begin the field with a minus sign if time must be subtracted from UTC.
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.TP
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.B RULES/SAVE
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The name of the rule(s) that apply in the time zone or,
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alternately, an amount of time to add to local standard time.
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If this field is
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.B \-
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then standard time always applies in the time zone.
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.TP
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.B FORMAT
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The format for time zone abbreviations in this time zone.
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The pair of characters
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.B %s
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is used to show where the
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.q "variable part"
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of the time zone abbreviation goes.
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Alternately,
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a slash (/)
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separates standard and daylight abbreviations.
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.TP
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.B UNTIL
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The time at which the UTC offset or the rule(s) change for a location.
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It is specified as a year, a month, a day, and a time of day.
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If this is specified,
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the time zone information is generated from the given UTC offset
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and rule change until the time specified.
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The month, day, and time of day have the same format as the IN, ON, and AT
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columns of a rule; trailing columns can be omitted, and default to the
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earliest possible value for the missing columns.
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.IP
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The next line must be a
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.q continuation
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line; this has the same form as a zone line except that the
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string
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.q Zone
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and the name are omitted, as the continuation line will
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place information starting at the time specified as the
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.B UNTIL
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field in the previous line in the file used by the previous line.
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Continuation lines may contain an
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.B UNTIL
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field, just as zone lines do, indicating that the next line is a further
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continuation.
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.PP
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A link line has the form
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.sp
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.nf
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.ti +.5i
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.ta \w'Link\0\0'u +\w'Europe/Istanbul\0\0'u
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Link LINK-FROM LINK-TO
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.sp
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For example:
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.sp
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.ti +.5i
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Link Europe/Istanbul Asia/Istanbul
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.sp
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.fi
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The
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.B LINK-FROM
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field should appear as the
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.B NAME
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field in some zone line;
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the
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.B LINK-TO
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field is used as an alternate name for that zone.
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.PP
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Except for continuation lines,
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lines may appear in any order in the input.
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.PP
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Lines in the file that describes leap seconds have the following form:
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.nf
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.ti +.5i
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.ta \w'Leap\0\0'u +\w'YEAR\0\0'u +\w'MONTH\0\0'u +\w'DAY\0\0'u +\w'HH:MM:SS\0\0'u +\w'CORR\0\0'u
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.sp
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Leap YEAR MONTH DAY HH:MM:SS CORR R/S
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.sp
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For example:
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.ti +.5i
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.sp
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Leap 1974 Dec 31 23:59:60 + S
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.sp
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.fi
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The
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.BR YEAR ,
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.BR MONTH ,
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.BR DAY ,
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and
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.B HH:MM:SS
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fields tell when the leap second happened.
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The
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.B CORR
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field
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should be
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.q +
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if a second was added
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or
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.q -
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if a second was skipped.
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.\" There's no need to document the following, since it's impossible for more
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.\" than one leap second to be inserted or deleted at a time.
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.\" The C Standard is in error in suggesting the possibility.
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.\" See Terry J Quinn, The BIPM and the accurate measure of time,
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.\" Proc IEEE 79, 7 (July 1991), 894-905.
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.\" or
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.\" .q ++
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.\" if two seconds were added
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.\" or
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.\" .q --
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.\" if two seconds were skipped.
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The
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.B R/S
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field
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should be (an abbreviation of)
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.q Stationary
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if the leap second time given by the other fields should be interpreted as UTC
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or
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(an abbreviation of)
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.q Rolling
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if the leap second time given by the other fields should be interpreted as
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local wall clock time.
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.SH NOTES
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For areas with more than two types of local time,
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you may need to use local standard time in the
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.B AT
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field of the earliest transition time's rule to ensure that
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the earliest transition time recorded in the compiled file is correct.
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.PP
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If,
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for a particular zone,
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a clock advance caused by the start of daylight saving
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coincides with and is equal to
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a clock retreat caused by a change in UTC offset,
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.IR zic
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produces a single transition to daylight saving at the new UTC offset
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(without any change in wall clock time).
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To get separate transitions
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use multiple zone continuation lines
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specifying transition instants using universal time.
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.SH FILE
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/usr/share/zoneinfo standard directory used for created files
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.SH "SEE ALSO"
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newctime(3), tzfile(5), zdump(8)
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.\" @(#)zic.8 7.24
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