Hi Paul,
On 06/27/2018 09:52 PM, Paul Eggert wrote:
> Make zic.8 a copy of the upstream tzdb version, except that
> the tzdb version's first line is replaced by man-pages
> boilerplate, and omit features introduced after 2017b
> (the most recent merge to glibc).
>
> This has the following effect:
>
> Document --version, --help.
>
> Document new -v warnings.
>
> Remove -y.
>
> Document that input should be text files, and similar restrictions on
> names.
>
> Document negative DST.
>
> Document what is meant by "white space".
>
> Do some minor reformatting.
>
> Use .B for as-is keywords, like commands.
>
> New section "EXTENDED EXAMPLE".
>
> Omit some changes that were made on the man-pages side, notably by
> changing some "timezone"s back to the preferred-upstream "time zone"
> when talking about traditional time zones as opposed to POSIX timezone
> settings. Also, fix some formatting glitches.
Patch applied. Thanks!
Cheers,
Michael
> ---
> man8/zic.8 | 516 +++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 358 insertions(+), 158 deletions(-)
>
> diff --git a/man8/zic.8 b/man8/zic.8
> index d56cad870..256a2ac77 100644
> --- a/man8/zic.8
> +++ b/man8/zic.8
> @@ -6,20 +6,32 @@
> .SH NAME
> zic \- timezone compiler
> .SH SYNOPSIS
> -.nf
> -.BR zic " [" \-v "] [" \-d " \fIdirectory\fP] [" \-l " \fIlocaltime\fP] [" \
> -\-p " \fIposixrules\fP]"
> -.RB " [" \-L " \fIleapsecondfilename\fP] [" \-s "] [" \-y \
> -" \fIcommand\fP] [\fIfilename\fP...]
> -.fi
> +.B zic
> +[
> +.I option
> +\&... ] [
> +.I filename
> +\&... ]
> .SH DESCRIPTION
> -.if t .ds lq ``
> -.if t .ds rq ''
> -.if n .ds lq \&"\"
> -.if n .ds rq \&"\"
> +.ie '\(lq'' .ds lq \&"\"
> +.el .ds lq \(lq\"
> +.ie '\(rq'' .ds rq \&"\"
> +.el .ds rq \(rq\"
> .de q
> \\$3\*(lq\\$1\*(rq\\$2
> ..
> +.ie '\(la'' .ds < <
> +.el .ds < \(la
> +.ie '\(ra'' .ds > >
> +.el .ds > \(ra
> +.ie \n(.g \{\
> +. ds : \:
> +. ds - \f(CW-\fP
> +.\}
> +.el \{\
> +. ds :
> +. ds - \-
> +.\}
> The
> .B zic
> program reads text from the file(s) named on the command line
> @@ -27,57 +39,116 @@ and creates the time conversion information files specified in this input.
> If a
> .I filename
> is
> -.BR \- ,
> +.q "\*-" ,
> standard input is read.
> -.PP
> -These options are available:
> +.SH OPTIONS
> .TP
> -.BI "\-d " directory
> +.B "\*-\*-version"
> +Output version information and exit.
> +.TP
> +.B \*-\*-help
> +Output short usage message and exit.
> +.TP
> +.BI "\*-d " directory
> Create time conversion information files in the named directory rather than
> in the standard directory named below.
> .TP
> -.BI "\-l " timezone
> -Use the given timezone as local time.
> +.BI "\*-l " timezone
> +Use
> +.I timezone
> +as local time.
> .B zic
> will act as if the input contained a link line of the form
> -.PP
> +.sp
> .ti +.5i
> Link \fItimezone\fP localtime
> .TP
> -.BI "\-p " timezone
> -Use the given timezone's rules when handling POSIX-format
> +.BI "\*-p " timezone
> +Use
> +.IR timezone 's
> +rules when handling POSIX-format
> timezone environment variables.
> .B zic
> will act as if the input contained a link line of the form
> -.PP
> +.sp
> .ti +.5i
> Link \fItimezone\fP posixrules
> .TP
> -.BI "\-L " leapsecondfilename
> +.BI "\*-L " leapsecondfilename
> Read leap second information from the file with the given name.
> If this option is not used,
> no leap second information appears in output files.
> .TP
> -.B \-v
> -Complain if a year that appears in a data file is outside the range
> +.B \*-v
> +Be more verbose, and complain about the following situations:
> +.RS
> +.PP
> +The input specifies a link to a link.
> +.PP
> +A year that appears in a data file is outside the range
> of years representable by
> .BR time (2)
> values.
> +.PP
> +A time of 24:00 or more appears in the input.
> +Pre-1998 versions of
> +.B zic
> +prohibit 24:00, and pre-2007 versions prohibit times greater than 24:00.
> +.PP
> +A rule goes past the start or end of the month.
> +Pre-2004 versions of
> +.B zic
> +prohibit this.
> +.PP
> +The output file does not contain all the information about the
> +long-term future of a timezone, because the future cannot be summarized as
> +an extended POSIX TZ string. For example, as of 2013 this problem
> +occurs for Iran's daylight-saving rules for the predicted future, as
> +these rules are based on the Iranian calendar, which cannot be
> +represented.
> +.PP
> +The output contains data that may not be handled properly by client
> +code designed for older
> +.B zic
> +output formats. These compatibility issues affect only timestamps
> +before 1970 or after the start of 2038.
> +.PP
> +A time zone abbreviation has fewer than 3 characters.
> +POSIX requires at least 3.
> +.PP
> +An output file name contains a byte that is not an ASCII letter,
> +.q "\*-" ,
> +.q "/" ,
> +or
> +.q "_" ;
> +or it contains a file name component that contains more than 14 bytes
> +or that starts with
> +.q "\*-" .
> +.RE
> .TP
> -.B \-s
> +.B \*-s
> Limit time values stored in output files to values that are the same
> whether they're taken to be signed or unsigned.
> You can use this option to generate SVVS-compatible files.
> -.TP
> -.BI "\-y " command
> -Use the given
> -.I command
> -rather than
> -.B yearistype
> -when checking year types (see below).
> +.PP
> +Input files should be text files, that is, they should be a series of
> +zero or more lines, each ending in a newline byte and containing at
> +most 511 bytes, and without any NUL bytes. The input text's encoding
> +is typically UTF-8 or ASCII; it should have a unibyte representation
> +for the POSIX Portable Character Set (PPCS)
> +\*<http://pubs\*:.opengroup\*:.org/\*:onlinepubs/\*:9699919799/\*:basedefs/\*:V1_chap06\*:.html\*>
> +and the encoding's non-unibyte characters should consist entirely of
> +non-PPCS bytes. Non-PPCS characters typically occur only in comments:
> +although output file names and time zone abbreviations can contain
> +nearly any character, other software will work better if these are
> +limited to the restricted syntax described under the
> +.B \*-v
> +option.
> .PP
> Input lines are made up of fields.
> -Fields are separated from one another by any number of white space characters.
> +Fields are separated from one another by one or more white space characters.
> +The white space characters are space, form feed, carriage return, newline,
> +tab, and vertical tab.
> Leading and trailing white space on input lines is ignored.
> An unquoted sharp character (#) in the input introduces a comment which extends
> to the end of the line the sharp character appears on.
> @@ -87,33 +158,53 @@ Any line that is blank (after comment stripping) is ignored.
> Nonblank lines are expected to be of one of three types:
> rule lines, zone lines, and link lines.
> .PP
> +Names must be in English and are case insensitive.
> +They appear in several contexts, and include month and weekday names
> +and keywords such as
> +.BR "maximum" ,
> +.BR "only" ,
> +.BR "Rolling" ,
> +and
> +.BR "Zone" .
> +A name can be abbreviated by omitting all but an initial prefix; any
> +abbreviation must be unambiguous in context.
> +.PP
> A rule line has the form
> .nf
> .ti +.5i
> -.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
> -.PP
> +.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'2:00w\0\0'u +\w'1:00d\0\0'u
> +.sp
> Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
> -.PP
> +.sp
> For example:
> .ti +.5i
> -.PP
> -Rule US 1967 1973 \- Apr lastSun 2:00 1:00 D
> -.PP
> +.sp
> +Rule US 1967 1973 \*- Apr lastSun 2:00w 1:00 D
> +.sp
> .fi
> The fields that make up a rule line are:
> .TP "\w'LETTER/S'u"
> .B NAME
> -Gives the (arbitrary) name of the set of rules this rule is part of.
> +Gives the name of the rule set that contains this line.
> +The name must start with a character that is neither
> +an ASCII digit nor
> +.q \*-
> +nor
> +.q + .
> +To allow for future extensions,
> +an unquoted name should not contain characters from the set
> +.q !$%&'()*,/:;<=>?@[\e]^`{|}~ .
> .TP
> .B FROM
> Gives the first year in which the rule applies.
> -Any integer year can be supplied; the Gregorian calendar is assumed.
> +Any signed integer year can be supplied; the proleptic Gregorian calendar
> +is assumed, with year 0 preceding year 1.
> The word
> -.I minimum
> -(or an abbreviation) means the minimum year representable as an integer.
> +.B minimum
> +(or an abbreviation) means the indefinite past.
> The word
> -.I maximum
> -(or an abbreviation) means the maximum year representable as an integer.
> +.B maximum
> +(or an abbreviation) means the indefinite future.
> Rules can describe times that are not representable as time values,
> with the unrepresentable times ignored; this allows rules to be portable
> among hosts with differing time value types.
> @@ -121,41 +212,23 @@ among hosts with differing time value types.
> .B TO
> Gives the final year in which the rule applies.
> In addition to
> -.I minimum
> +.B minimum
> and
> -.I maximum
> +.B maximum
> (as above),
> the word
> -.I only
> +.B only
> (or an abbreviation)
> may be used to repeat the value of the
> .B FROM
> field.
> .TP
> .B TYPE
> -Gives the type of year in which the rule applies.
> -If
> -.B TYPE
> -is
> -.BR \- ,
> -then the rule applies in all years between
> -.B FROM
> -and
> -.B TO
> -inclusive.
> -If
> -.B TYPE
> -is something else, then
> -.I zic
> -executes the command
> -.ti +.5i
> -.B yearistype
> -.I year
> -.I type
> -.br
> -to check the type of a year:
> -an exit status of zero is taken to mean that the year is of the given type;
> -an exit status of one is taken to mean that the year is not of the given type.
> +should be
> +.q \*-
> +and is present for compatibility with older versions of
> +.B zic
> +in which it could contain year types.
> .TP
> .B IN
> Names the month in which the rule takes effect.
> @@ -166,7 +239,7 @@ Gives the day on which the rule takes effect.
> Recognized forms include:
> .nf
> .in +.5i
> -.PP
> +.sp
> .ta \w'Sun<=25\0\0'u
> 5 the fifth of the month
> lastSun the last Sunday in the month
> @@ -175,8 +248,14 @@ Sun>=8 first Sunday on or after the eighth
> Sun<=25 last Sunday on or before the 25th
> .fi
> .in -.5i
> -.PP
> -Names of days of the week may be abbreviated or spelled out in full.
> +.sp
> +A weekday name (e.g.,
> +.BR "Sunday" )
> +or a weekday name preceded by
> +.q "last"
> +(e.g.,
> +.BR "lastSunday" )
> +may be abbreviated or spelled out in full.
> Note that there must be no spaces within the
> .B ON
> field.
> @@ -186,35 +265,41 @@ Gives the time of day at which the rule takes effect.
> Recognized forms include:
> .nf
> .in +.5i
> -.PP
> -.ta \w'1:28:13\0\0'u
> +.sp
> +.ta \w'00:19:32.13\0\0'u
> 2 time in hours
> 2:00 time in hours and minutes
> +01:28:14 time in hours, minutes, and seconds
> 15:00 24-hour format time (for times after noon)
> -1:28:14 time in hours, minutes, and seconds
> -\- equivalent to 0
> +260:00 260 hours after 00:00
> +\*-2:30 2.5 hours before 00:00
> +\*- equivalent to 0
> .fi
> .in -.5i
> -.PP
> +.sp
> where hour 0 is midnight at the start of the day,
> and hour 24 is midnight at the end of the day.
> Any of these forms may be followed by the letter
> -.I w
> +.B w
> if the given time is local
> .q "wall clock"
> time,
> -.I s
> +.B s
> if the given time is local
> -.q standard
> +.q "standard"
> time, or
> -.I u
> +.B u
> (or
> -.I g
> +.B g
> or
> -.IR z )
> +.BR z )
> if the given time is universal time;
> in the absence of an indicator,
> wall clock time is assumed.
> +The intent is that a rule line describes the instants when a
> +clock/calendar set to the type of time specified in the
> +.B AT
> +field would show the specified date and time of day.
> .TP
> .B SAVE
> Gives the amount of time to be added to local standard time when the rule is in
> @@ -223,135 +308,184 @@ This field has the same format as the
> .B AT
> field
> (although, of course, the
> -.I w
> +.B w
> and
> -.I s
> +.B s
> suffixes are not used).
> +Negative offsets are allowed; in Ireland, for example, daylight saving
> +time is observed in winter and has a negative offset relative to
> +Irish Standard Time.
> +The offset is merely added to standard time; for example,
> +.B zic
> +does not distinguish a 10:30 standard time plus an 0:30
> +.B SAVE
> +from a 10:00 standard time plus a 1:00
> +.BR SAVE .
> .TP
> .B LETTER/S
> Gives the
> .q "variable part"
> (for example, the
> -.q S
> +.q "S"
> or
> -.q D
> +.q "D"
> in
> -.q EST
> +.q "EST"
> or
> -.q EDT )
> -of timezone abbreviations to be used when this rule is in effect.
> +.q "EDT" )
> +of time zone abbreviations to be used when this rule is in effect.
> If this field is
> -.BR \- ,
> +.q \*- ,
> the variable part is null.
> .PP
> A zone line has the form
> -.PP
> +.sp
> .nf
> .ti +.5i
> -.ta \w'Zone\0\0'u +\w'Australia/Adelaide\0\0'u +\w'UTCOFF\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u
> -Zone NAME UTCOFF RULES/SAVE FORMAT [UNTIL]
> -.PP
> +.ta \w'Zone\0\0'u +\w'Asia/Amman\0\0'u +\w'UTOFF\0\0'u +\w'Jordan\0\0'u +\w'FORMAT\0\0'u
> +Zone NAME UTOFF RULES FORMAT [UNTIL]
> +.sp
> For example:
> -.PP
> +.sp
> .ti +.5i
> -Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00
> -.PP
> +Zone Asia/Amman 2:00 Jordan EE%sT 2017 Oct 27 01:00
> +.sp
> .fi
> The fields that make up a zone line are:
> -.TP "\w'UTCOFF'u"
> +.TP "\w'UTOFF'u"
> .B NAME
> The name of the timezone.
> This is the name used in creating the time conversion information file for the
> -zone.
> +timezone.
> +It should not contain a file name component
> +.q ".\&"
> +or
> +.q ".." ;
> +a file name component is a maximal substring that does not contain
> +.q "/" .
> .TP
> -.B UTCOFF
> -The amount of time to add to UTC to get standard time in this zone.
> +.B UTOFF
> +The amount of time to add to UT to get standard time.
> This field has the same format as the
> .B AT
> and
> .B SAVE
> fields of rule lines;
> -begin the field with a minus sign if time must be subtracted from UTC.
> +begin the field with a minus sign if time must be subtracted from UT.
> .TP
> -.B RULES/SAVE
> -The name of the rule(s) that apply in the timezone or,
> -alternately, an amount of time to add to local standard time.
> +.B RULES
> +The name of the rules that apply in the timezone or,
> +alternatively, a field in the same format as a rule-line SAVE column,
> +giving of the amount of time to be added to local standard time
> +effect, and whether the resulting time is standard or daylight saving.
> If this field is
> -.BR \- ,
> -then standard time always applies in the timezone.
> +.B \*-
> +then standard time always applies.
> +When an amount of time is given, only the sum of standard time and
> +this amount matters.
> .TP
> .B FORMAT
> -The format for timezone abbreviations in this timezone.
> +The format for time zone abbreviations.
> The pair of characters
> .B %s
> is used to show where the
> .q "variable part"
> -of the timezone abbreviation goes.
> -Alternately,
> +of the time zone abbreviation goes.
> +Alternatively, a format can use the pair of characters
> +.B %z
> +to stand for the UT offset in the form
> +.RI \(+- hh ,
> +.RI \(+- hhmm ,
> +or
> +.RI \(+- hhmmss ,
> +using the shortest form that does not lose information, where
> +.IR hh ,
> +.IR mm ,
> +and
> +.I ss
> +are the hours, minutes, and seconds east (+) or west (\(mi) of UT.
> +Alternatively,
> a slash (/)
> separates standard and daylight abbreviations.
> +To conform to POSIX, a time zone abbreviation should contain only
> +alphanumeric ASCII characters,
> +.q "+"
> +and
> +.q "\*-".
> .TP
> .B UNTIL
> -The time at which the UTC offset or the rule(s) change for a location.
> -It is specified as a year, a month, a day, and a time of day.
> +The time at which the UT offset or the rule(s) change for a location.
> +It takes the form of YEAR [MONTH [DAY [TIME]]].
> If this is specified,
> -the timezone information is generated from the given UTC offset
> -and rule change until the time specified.
> +the time zone information is generated from the given UT offset
> +and rule change until the time specified, which is interpreted using
> +the rules in effect just before the transition.
> The month, day, and time of day have the same format as the IN, ON, and AT
> -columns of a rule; trailing columns can be omitted, and default to the
> -earliest possible value for the missing columns.
> +fields of a rule; trailing fields can be omitted, and default to the
> +earliest possible value for the missing fields.
> .IP
> The next line must be a
> -.q continuation
> +.q "continuation"
> line; this has the same form as a zone line except that the
> string
> -.q Zone
> +.q "Zone"
> and the name are omitted, as the continuation line will
> place information starting at the time specified as the
> -.B UNTIL
> -field in the previous line in the file used by the previous line.
> -Continuation lines may contain an
> -.B UNTIL
> -field, just as zone lines do, indicating that the next line is a further
> +.q "until"
> +information in the previous line in the file used by the previous line.
> +Continuation lines may contain
> +.q "until"
> +information, just as zone lines do, indicating that the next line is a further
> continuation.
> .PP
> -A link line has the form
> +If a zone changes at the same instant that a rule would otherwise take
> +effect in the earlier zone or continuation line, the rule is ignored.
> +In a single zone it is an error if two rules take effect at the same
> +instant, or if two zone changes take effect at the same instant.
> .PP
> +A link line has the form
> +.sp
> .nf
> .ti +.5i
> .ta \w'Link\0\0'u +\w'Europe/Istanbul\0\0'u
> -Link LINK-FROM LINK-TO
> -.PP
> +Link TARGET LINK-NAME
> +.sp
> For example:
> -.PP
> +.sp
> .ti +.5i
> Link Europe/Istanbul Asia/Istanbul
> -.PP
> +.sp
> .fi
> The
> -.B LINK-FROM
> +.B TARGET
> field should appear as the
> .B NAME
> -field in some zone line;
> -the
> -.B LINK-TO
> -field is used as an alternate name for that zone.
> +field in some zone line.
> +The
> +.B LINK-NAME
> +field is used as an alternative name for that zone;
> +it has the same syntax as a zone line's
> +.B NAME
> +field.
> .PP
> Except for continuation lines,
> lines may appear in any order in the input.
> +However, the behavior is unspecified if multiple zone or link lines
> +define the same name, or if the source of one link line is the target
> +of another.
> .PP
> Lines in the file that describes leap seconds have the following form:
> .nf
> .ti +.5i
> .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
> -.PP
> +.sp
> Leap YEAR MONTH DAY HH:MM:SS CORR R/S
> -.PP
> +.sp
> For example:
> .ti +.5i
> -.PP
> -Leap 1974 Dec 31 23:59:60 + S
> -.PP
> +.sp
> +Leap 2016 Dec 31 23:59:60 + S
> +.sp
> .fi
> The
> .BR YEAR ,
> @@ -364,44 +498,110 @@ The
> .B CORR
> field
> should be
> -.q +
> +.q "+"
> if a second was added
> or
> -.q -
> +.q "\*-"
> if a second was skipped.
> -.\" There's no need to document the following, since it's impossible for more
> -.\" than one leap second to be inserted or deleted at a time.
> -.\" The C Standard is in error in suggesting the possibility.
> -.\" See Terry J Quinn, The BIPM and the accurate measure of time,
> -.\" Proc IEEE 79, 7 (July 1991), 894-905.
> -.\" or
> -.\" .q ++
> -.\" if two seconds were added
> -.\" or
> -.\" .q --
> -.\" if two seconds were skipped.
> The
> .B R/S
> field
> should be (an abbreviation of)
> -.q Stationary
> +.q "Stationary"
> if the leap second time given by the other fields should be interpreted as UTC
> or
> (an abbreviation of)
> -.q Rolling
> +.q "Rolling"
> if the leap second time given by the other fields should be interpreted as
> local wall clock time.
> +.SH "EXTENDED EXAMPLE"
> +Here is an extended example of
> +.B zic
> +input, intended to illustrate many of its features.
> +In this example, the EU rules are for the European Union
> +and for its predecessor organization, the European Communities.
> +.br
> +.ne 22
> +.nf
> +.in +2m
> +.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
> +.sp
> +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
> +Rule Swiss 1941 1942 \*- May Mon>=1 1:00 1:00 S
> +Rule Swiss 1941 1942 \*- Oct Mon>=1 2:00 0 \*-
> +.sp .5
> +Rule EU 1977 1980 \*- Apr Sun>=1 1:00u 1:00 S
> +Rule EU 1977 only \*- Sep lastSun 1:00u 0 \*-
> +Rule EU 1978 only \*- Oct 1 1:00u 0 \*-
> +Rule EU 1979 1995 \*- Sep lastSun 1:00u 0 \*-
> +Rule EU 1981 max \*- Mar lastSun 1:00u 1:00 S
> +Rule EU 1996 max \*- Oct lastSun 1:00u 0 \*-
> +.sp
> +.ta \w'# Zone\0\0'u +\w'Europe/Zurich\0\0'u +\w'0:34:08\0\0'u +\w'RULES\0\0'u +\w'FORMAT\0\0'u
> +# Zone NAME UTOFF RULES FORMAT [UNTIL]
> +Zone Europe/Zurich 0:34:08 \*- LMT 1853 Jul 16
> + 0:29:46 \*- BMT 1894 Jun
> + 1:00 Swiss CE%sT 1981
> + 1:00 EU CE%sT
> +.sp
> +Link Europe/Zurich Europe/Vaduz
> +.sp
> +.in
> +.fi
> +In this example, the timezone is named Europe/Zurich but it has an alias
> +as Europe/Vaduz. This example says that Zurich was 34 minutes and 8
> +seconds east of UT until 1853-07-16 at 00:00, when the legal offset
> +was changed to 7\(de\|26\(fm\|22.50\(sd; although this works out to
> +0:29:45.50, the input format cannot represent fractional seconds so it
> +is rounded here. After 1894-06-01 at 00:00 the UT offset became one hour
> +and Swiss daylight saving rules (defined with lines beginning with
> +.q "Rule Swiss")
> +apply. From 1981 to the present, EU daylight saving rules have
> +applied, and the UTC offset has remained at one hour.
> +.PP
> +In 1941 and 1942, daylight saving time applied from the first Monday
> +in May at 01:00 to the first Monday in October at 02:00.
> +The pre-1981 EU daylight-saving rules have no effect
> +here, but are included for completeness. Since 1981, daylight
> +saving has begun on the last Sunday in March at 01:00 UTC.
> +Until 1995 it ended the last Sunday in September at 01:00 UTC,
> +but this changed to the last Sunday in October starting in 1996.
> +.PP
> +For purposes of display,
> +.q "LMT"
> +and
> +.q "BMT"
> +were initially used, respectively. Since
> +Swiss rules and later EU rules were applied, the time zone abbreviation
> +has been CET for standard time and CEST for daylight saving
> +time.
> .SH FILES
> .TP
> -.I /usr/local/etc/zoneinfo
> -Standard directory used for created files.
> +.I /etc/localtime
> +Default local timezone file.
> +.TP
> +.I /usr/share/zoneinfo
> +Default timezone information directory.
> .SH NOTES
> For areas with more than two types of local time,
> you may need to use local standard time in the
> .B AT
> field of the earliest transition time's rule to ensure that
> the earliest transition time recorded in the compiled file is correct.
> +.PP
> +If,
> +for a particular timezone,
> +a clock advance caused by the start of daylight saving
> +coincides with and is equal to
> +a clock retreat caused by a change in UT offset,
> +.B zic
> +produces a single transition to daylight saving at the new UT offset
> +(without any change in wall clock time).
> +To get separate transitions
> +use multiple zone continuation lines
> +specifying transition instants using universal time.
> .SH SEE ALSO
> .BR tzfile (5),
> .BR zdump (8)
> -.\" @(#)zic.8 7.19
> +.\" This file is in the public domain, so clarified as of
> +.\" 2009-05-17 by Arthur David Olson.
>
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
