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Diffstat (limited to 'time/tzselect.ksh')
| -rw-r--r-- | time/tzselect.ksh | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/time/tzselect.ksh b/time/tzselect.ksh new file mode 100644 index 0000000..0f0a3bb --- /dev/null +++ b/time/tzselect.ksh @@ -0,0 +1,292 @@ +#! /bin/ksh +# Ask the user about the time zone, and output the resulting TZ value to stdout. +# Interact with the user via stderr and stdin. + +# Contributed by Paul Eggert <eggert@twinsun.com>. + +# Porting notes: +# +# This script requires several features of the Korn shell. +# If your host lacks the Korn shell, +# you can use either of the following free programs instead: +# +# Bourne-Again shell (bash) +# <URL:ftp://prep.ai.mit.edu:/pub/gnu/bash-1.14.7.tar.gz> +# (or any later version) +# +# Public domain ksh +# <URL:ftp://ftp.cs.mun.ca:/pub/pdksh/pdksh.tar.gz> +# +# This script also uses several features of modern awk programs. +# If your host lacks awk, or has an old awk that does not conform to Posix.2, +# you can use either of the following free programs instead: +# +# GNU awk (gawk) +# <URL:ftp://prep.ai.mit.edu:/pub/gnu/gawk-3.0.0.tar.gz> +# (or any later version) +# +# mawk +# <URL:ftp://oxy.edu/public/mawk1.2.2.tar.gz> +# (or any later version) + + +# Specify default values for environment variables if they are unset. +: ${AWK=awk} +: ${TZDIR=$(pwd)} + +# Check for awk Posix compliance. +($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1 +[ $? = 123 ] || { + echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible." + exit 1 +} + +# Make sure the tables are readable. +TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab +TZ_ZONE_TABLE=$TZDIR/zone.tab +for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE +do + <$f || { + echo >&2 "$0: time zone files are not set up correctly" + exit 1 + } +done + +newline=' +' +IFS=$newline + + +# Work around a bash bug, where $PS3 is sent to stdout. +case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in +?*) PS3= +esac + + +# Begin the main loop. We come back here if the user wants to retry. +while + + echo >&2 'Please identify a location' \ + 'so that time zone rules can be set correctly.' + + continent= + country= + region= + + + # Ask the user for continent or ocean. + + echo >&2 'Please select a continent or ocean.' + + select continent in \ + Africa \ + Americas \ + Antarctica \ + 'Arctic Ocean' \ + Asia \ + 'Atlantic Ocean' \ + Australia \ + Europe \ + 'Indian Ocean' \ + 'Pacific Ocean' \ + 'none - I want to specify the time zone using the Posix TZ format.' + do + case $continent in + '') + echo >&2 'Please enter a number in range.';; + ?*) + case $continent in + Americas) continent=America;; + *' '*) continent=$(expr "$continent" : '\([^ ]*\)') + esac + break + esac + done + case $continent in + '') + exit 1;; + none) + # Ask the user for a Posix TZ string. Check that it conforms. + while + echo >&2 'Please enter the desired value' \ + 'of the TZ environment variable.' + echo >&2 'For example, GST-10 is a zone named GST' \ + 'that is 10 hours ahead (east) of UTC.' + read TZ + $AWK -v TZ="$TZ" 'BEGIN { + tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+" + time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?" + offset = "[-+]?" time + date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)" + datetime = "," date "(/" time ")?" + tzpattern = "^(:.*|" tzname offset "(" tzname \ + "(" offset ")?(" datetime datetime ")?)?)$" + if (TZ ~ tzpattern) exit 1 + exit 0 + }' + do + echo >&2 "\`$TZ' is not a conforming" \ + 'Posix time zone string.' + done + TZ_for_date=$TZ;; + *) + # Get list of names of countries in the continent or ocean. + countries=$($AWK -F'\t' \ + -v continent="$continent" \ + -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ + ' + /^#/ { next } + $3 ~ ("^" continent "/") { + if (!cc_seen[$1]++) cc_list[++ccs] = $1 + } + END { + while (getline <TZ_COUNTRY_TABLE) { + if ($0 !~ /^#/) cc_name[$1] = $2 + } + for (i = 1; i <= ccs; i++) { + country = cc_list[i] + if (cc_name[country]) { + country = cc_name[country] + } + print country + } + } + ' <$TZ_ZONE_TABLE | sort -f) + + + # If there's more than one country, ask the user which one. + case $countries in + *"$newline"*) + echo >&2 'Please select a country.' + select country in $countries + do + case $country in + '') echo >&2 'Please enter a number in range.';; + ?*) break + esac + done + + case $country in + '') exit 1 + esac;; + *) + country=$countries + esac + + + # Get list of names of time zone rule regions in the country. + regions=$($AWK -F'\t' \ + -v country="$country" \ + -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ + ' + BEGIN { + cc = country + while (getline <TZ_COUNTRY_TABLE) { + if ($0 !~ /^#/ && country == $2) { + cc = $1 + break + } + } + } + $1 == cc { print $4 } + ' <$TZ_ZONE_TABLE) + + + # If there's more than one region, ask the user which one. + case $regions in + *"$newline"*) + echo >&2 'Please select one of the following' \ + 'time zone regions.' + select region in $regions + do + case $region in + '') echo >&2 'Please enter a number in range.';; + ?*) break + esac + done + case $region in + '') exit 1 + esac;; + *) + region=$regions + esac + + # Determine TZ from country and region. + TZ=$($AWK -F'\t' \ + -v country="$country" \ + -v region="$region" \ + -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ + ' + BEGIN { + cc = country + while (getline <TZ_COUNTRY_TABLE) { + if ($0 !~ /^#/ && country == $2) { + cc = $1 + break + } + } + } + $1 == cc && $4 == region { print $3 } + ' <$TZ_ZONE_TABLE) + + # Make sure the corresponding zoneinfo file exists. + TZ_for_date=$TZDIR/$TZ + <$TZ_for_date || { + echo >&2 "$0: time zone files are not set up correctly" + exit 1 + } + esac + + + # Use the proposed TZ to output the current date relative to UTC. + # Loop until they agree in seconds. + # Give up after 8 unsuccessful tries. + + extra_info= + for i in 1 2 3 4 5 6 7 8 + do + TZdate=$(LANG=C TZ="$TZ_for_date" date) + UTdate=$(LANG=C TZ=UTC0 date) + TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)') + UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)') + case $TZsec in + $UTsec) + extra_info=" +Local time is now: $TZdate. +Universal Time is now: $UTdate." + break + esac + done + + + # Output TZ info and ask the user to confirm. + + echo >&2 "" + echo >&2 "The following information has been given:" + echo >&2 "" + case $country+$region in + ?*+?*) echo >&2 " $country$newline $region";; + ?*+) echo >&2 " $country";; + +) echo >&2 " TZ='$TZ'" + esac + echo >&2 "" + echo >&2 "Therefore TZ='$TZ' will be used.$extra_info" + echo >&2 "Is the above information OK?" + + ok= + select ok in Yes No + do + case $ok in + '') echo >&2 'Please enter 1 for Yes, or 2 for No.';; + ?*) break + esac + done + case $ok in + '') exit 1;; + Yes) break + esac +do : +done + +# Output the answer. +echo "$TZ" |