#!/bin/bash # Ask the user about the time zone, and output the resulting TZ value to stdout. # Interact with the user via stderr and stdin. PKGVERSION='(tzcode) ' TZVERSION=see_Makefile REPORT_BUGS_TO=tz@iana.org # Contributed by Paul Eggert. This file is in the public domain. # Porting notes: # # This script requires a POSIX-like shell and prefers the extension of a # 'select' statement. The 'select' statement was introduced in the # Korn shell and is available in Bash and other shell implementations. # If your host lacks both Bash and the Korn shell, you can get their # source from one of these locations: # # Bash # Korn Shell # MirBSD Korn Shell # # For portability to Solaris 10 /bin/sh (supported by Oracle through # January 2027) this script avoids some POSIX features and common # extensions, such as $(...), $((...)), ! CMD, unquoted ^, ${#ID}, # ${ID##PAT}, ${ID%%PAT}, and $10. Although some of these constructs # work sometimes, it's simpler to avoid them entirely. # # This script also uses several features of POSIX awk. # If your host lacks awk, or has an old awk that does not conform to POSIX, # you can use any of the following free programs instead: # # Gawk (GNU awk) # mawk # nawk # # Because 'awk "VAR=VALUE" ...' and 'awk -v "VAR=VALUE" ...' are not portable # if VALUE contains \, ", or newline, awk scripts in this file use: # awk 'BEGIN { VAR = substr(ARGV[1], 2); ARGV[1] = "" } ...' ="VALUE" # The substr avoids problems when VALUE is of the form X=Y and would be # misinterpreted as an assignment. # This script does not want path expansion. set -f # Specify default values for environment variables if they are unset. : ${AWK=awk} : ${PWD=`pwd`} : ${TZDIR=$PWD} # Output one argument as-is to standard output, with trailing newline. # Safer than 'echo', which can mishandle '\' or leading '-'. say() { printf '%s\n' "$1" } # Check for awk POSIX compliance. ($AWK -v x=y 'BEGIN { exit 123 }') <>/dev/null >&0 2>&0 [ $? = 123 ] || { say >&2 "$0: Sorry, your '$AWK' program is not POSIX compatible." exit 1 } coord= location_limit=10 zonetabtype=zone1970 usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT] Select a timezone interactively. Options: -c COORD Instead of asking for continent and then country and then city, ask for selection from time zones whose largest cities are closest to the location with geographical coordinates COORD. COORD should use ISO 6709 notation, for example, '-c +4852+00220' for Paris (in degrees and minutes, North and East), or '-c -35-058' for Buenos Aires (in degrees, South and West). -n LIMIT Display at most LIMIT locations when -c is used (default $location_limit). --version Output version information. --help Output this help. Report bugs to $REPORT_BUGS_TO." # Ask the user to select from the function's arguments, # and assign the selected argument to the variable 'select_result'. # Exit on EOF or I/O error. Use the shell's nicer 'select' builtin if # available, falling back on a portable substitute otherwise. if case $BASH_VERSION in ?*) :;; '') # '; exit' should be redundant, but Dash doesn't properly fail without it. (eval 'set --; select x; do break; done; exit') <>/dev/null 2>&0 esac then # Do this inside 'eval', as otherwise the shell might exit when parsing it # even though it is never executed. eval ' doselect() { select select_result do case $select_result in "") echo >&2 "Please enter a number in range.";; ?*) break esac done || exit } ' else doselect() { # Field width of the prompt numbers. print_nargs_length="BEGIN {print length(\"$#\");}" select_width=`$AWK "$print_nargs_length"` select_i= while : do case $select_i in '') select_i=0 for select_word do select_i=`$AWK "BEGIN { print $select_i + 1 }"` printf >&2 "%${select_width}d) %s\\n" $select_i "$select_word" done;; *[!0-9]*) echo >&2 'Please enter a number in range.';; *) if test 1 -le $select_i && test $select_i -le $#; then shift `$AWK "BEGIN { print $select_i - 1 }"` select_result=$1 break fi echo >&2 'Please enter a number in range.' esac # Prompt and read input. printf >&2 %s "${PS3-#? }" read select_i || exit done } fi while getopts c:n:t:-: opt do case $opt$OPTARG in c*) coord=$OPTARG;; n*) location_limit=$OPTARG;; t*) # Undocumented option, used for developer testing. zonetabtype=$OPTARG;; -help) exec echo "$usage";; -version) exec echo "tzselect $PKGVERSION$TZVERSION";; -*) say >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1;; *) say >&2 "$0: try '$0 --help'"; exit 1 esac done shift `$AWK "BEGIN { print $OPTIND - 1 }"` case $# in 0) ;; *) say >&2 "$0: $1: unknown argument"; exit 1 esac # translit=true to try transliteration. # This is false if U+12345 CUNEIFORM SIGN URU TIMES KI has length 1 # which means awk (and presumably the shell) do not need transliteration. if $AWK 'BEGIN { u12345 = "\360\222\215\205"; exit length(u12345) == 1 }'; then translit=true else translit=false fi # Read into shell variable $1 the contents of file $2. # Convert to the current locale's encoding if possible, # as the shell aligns columns better that way. # If GNU iconv's //TRANSLIT does not work, fall back on POSIXish iconv; # if that does not work, fall back on 'cat'. read_file() { { $translit && { eval "$1=\`(iconv -f UTF-8 -t //TRANSLIT) 2>/dev/null <\"\$2\"\`" || eval "$1=\`(iconv -f UTF-8) 2>/dev/null <\"\$2\"\`" }; } || eval "$1=\`cat <\"\$2\"\`" || { say >&2 "$0: time zone files are not set up correctly" exit 1 } } read_file TZ_COUNTRY_TABLE "$TZDIR/iso3166.tab" read_file TZ_ZONETABTYPE_TABLE "$TZDIR/$zonetabtype.tab" TZ_ZONENOW_TABLE= newline=' ' IFS=$newline # Awk script to output a country list. output_country_list=' BEGIN { continent_re = substr(ARGV[1], 2) TZ_COUNTRY_TABLE = substr(ARGV[2], 2) TZ_ZONE_TABLE = substr(ARGV[3], 2) ARGV[1] = ARGV[2] = ARGV[3] = "" FS = "\t" nlines = split(TZ_ZONE_TABLE, line, /\n/) for (iline = 1; iline <= nlines; iline++) { $0 = line[iline] commentary = $0 ~ /^#@/ if (commentary) { if ($0 !~ /^#@/) continue col1ccs = substr($1, 3) conts = $2 } else { col1ccs = $1 conts = $3 } ncc = split(col1ccs, cc, /,/) ncont = split(conts, cont, /,/) for (i = 1; i <= ncc; i++) { elsewhere = commentary for (ci = 1; ci <= ncont; ci++) { if (cont[ci] ~ continent_re) { if (!cc_seen[cc[i]]++) cc_list[++ccs] = cc[i] elsewhere = 0 } } if (elsewhere) for (i = 1; i <= ncc; i++) cc_elsewhere[cc[i]] = 1 } } nlines = split(TZ_COUNTRY_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 !~ /^#/) cc_name[$1] = $2 } for (i = 1; i <= ccs; i++) { country = cc_list[i] if (cc_elsewhere[country]) continue if (cc_name[country]) country = cc_name[country] print country } } ' # Awk script to process a time zone table and output the same table, # with each row preceded by its distance from 'here'. # If output_times is set, each row is instead preceded by its local time # and any apostrophes are escaped for the shell. output_distances_or_times=' BEGIN { coord = substr(ARGV[1], 2) TZ_COUNTRY_TABLE = substr(ARGV[2], 2) TZ_ZONE_TABLE = substr(ARGV[3], 2) ARGV[1] = ARGV[2] = ARGV[3] = "" FS = "\t" if (!output_times) { nlines = split(TZ_COUNTRY_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 ~ /^#/) continue country[$1] = $2 } country["US"] = "US" # Otherwise the strings get too long. } } function abs(x) { return x < 0 ? -x : x; } function min(x, y) { return x < y ? x : y; } function convert_coord(coord, deg, minute, ilen, sign, sec) { if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9][0-9][0-9]([^0-9]|$)/) { degminsec = coord intdeg = degminsec < 0 ? -int(-degminsec / 10000) : int(degminsec / 10000) minsec = degminsec - intdeg * 10000 intmin = minsec < 0 ? -int(-minsec / 100) : int(minsec / 100) sec = minsec - intmin * 100 deg = (intdeg * 3600 + intmin * 60 + sec) / 3600 } else if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9]([^0-9]|$)/) { degmin = coord intdeg = degmin < 0 ? -int(-degmin / 100) : int(degmin / 100) minute = degmin - intdeg * 100 deg = (intdeg * 60 + minute) / 60 } else deg = coord return deg * 0.017453292519943296 } function convert_latitude(coord) { match(coord, /..*[-+]/) return convert_coord(substr(coord, 1, RLENGTH - 1)) } function convert_longitude(coord) { match(coord, /..*[-+]/) return convert_coord(substr(coord, RLENGTH)) } # Great-circle distance between points with given latitude and longitude. # Inputs and output are in radians. This uses the great-circle special # case of the Vicenty formula for distances on ellipsoids. function gcdist(lat1, long1, lat2, long2, dlong, x, y, num, denom) { dlong = long2 - long1 x = cos(lat2) * sin(dlong) y = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dlong) num = sqrt(x * x + y * y) denom = sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(dlong) return atan2(num, denom) } # Parallel distance between points with given latitude and longitude. # This is the product of the longitude difference and the cosine # of the latitude of the point that is further from the equator. # I.e., it considers longitudes to be further apart if they are # nearer the equator. function pardist(lat1, long1, lat2, long2) { return abs(long1 - long2) * min(cos(lat1), cos(lat2)) } # The distance function is the sum of the great-circle distance and # the parallel distance. It could be weighted. function dist(lat1, long1, lat2, long2) { return gcdist(lat1, long1, lat2, long2) + pardist(lat1, long1, lat2, long2) } BEGIN { coord_lat = convert_latitude(coord) coord_long = convert_longitude(coord) nlines = split(TZ_ZONE_TABLE, line, /\n/) for (h = 1; h <= nlines; h++) { $0 = line[h] if ($0 ~ /^#/) continue inline[inlines++] = $0 ncc = split($1, cc, /,/) for (i = 1; i <= ncc; i++) cc_used[cc[i]]++ } for (h = 0; h < inlines; h++) { $0 = inline[h] outline = $1 "\t" $2 "\t" $3 sep = "\t" ncc = split($1, cc, /,/) split("", item_seen) item_seen[""] = 1 for (i = 1; i <= ncc; i++) { item = cc_used[cc[i]] <= 1 ? country[cc[i]] : $4 if (item_seen[item]++) continue outline = outline sep item sep = "; " } if (output_times) { fmt = "TZ='\''%s'\'' date +'\''%d %%Y %%m %%d %%H:%%M %%a %%b\t%s'\''\n" gsub(/'\''/, "&\\\\&&", outline) printf fmt, $3, h, outline } else { here_lat = convert_latitude($2) here_long = convert_longitude($2) printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), \ outline } } } ' # Begin the main loop. We come back here if the user wants to retry. while echo >&2 'Please identify a location' \ 'so that time zone rules can be set correctly.' continent= country= country_result= region= time= TZ_ZONE_TABLE=$TZ_ZONETABTYPE_TABLE case $coord in ?*) continent=coord;; '') # Ask the user for continent or ocean. echo >&2 \ 'Please select a continent, ocean, "coord", "TZ", "time", or "now".' quoted_continents=` $AWK ' function handle_entry(entry) { entry = substr(entry, 1, index(entry, "/") - 1) if (entry == "America") entry = entry "s" if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/) entry = entry " Ocean" printf "'\''%s'\''\n", entry } BEGIN { TZ_ZONETABTYPE_TABLE = substr(ARGV[1], 2) ARGV[1] = "" FS = "\t" nlines = split(TZ_ZONETABTYPE_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 ~ /^[^#]/) handle_entry($3) else if ($0 ~ /^#@/) { ncont = split($2, cont, /,/) for (ci = 1; ci <= ncont; ci++) handle_entry(cont[ci]) } } } ' ="$TZ_ZONETABTYPE_TABLE" | sort -u | tr '\n' ' ' echo '' ` eval ' doselect '"$quoted_continents"' \ "coord - I want to use geographical coordinates." \ "TZ - I want to specify the timezone using a POSIX.1-2017 TZ string." \ "time - I know local time already." \ "now - Like \"time\", but configure only for timestamps from now on." continent=$select_result case $continent in Americas) continent=America;; *) # Get the first word of $continent. Path expansion is disabled # so this works even with "*", which should not happen. IFS=" " for continent in $continent ""; do break; done IFS=$newline;; esac case $zonetabtype,$continent in zonenow,*) ;; *,now) ${TZ_ZONENOW_TABLE:+:} read_file TZ_ZONENOW_TABLE "$TZDIR/zonenow.tab" TZ_ZONE_TABLE=$TZ_ZONENOW_TABLE esac ' esac case $continent in TZ) # Ask the user for a POSIX.1-2017 TZ string. Check that it conforms. check_POSIX_TZ_string=' BEGIN { tz = substr(ARGV[1], 2) ARGV[1] = "" tzname = ("(<[[:alnum:]+-][[:alnum:]+-][[:alnum:]+-]+>" \ "|[[:alpha:]][[:alpha:]][[:alpha:]]+)") time = ("(2[0-4]|[0-1]?[0-9])" \ "(:[0-5][0-9](:[0-5][0-9])?)?") offset = "[-+]?" time mdate = "M([1-9]|1[0-2])\\.[1-5]\\.[0-6]" jdate = ("((J[1-9]|[0-9]|J?[1-9][0-9]" \ "|J?[1-2][0-9][0-9])|J?3[0-5][0-9]|J?36[0-5])") datetime = ",(" mdate "|" jdate ")(/" time ")?" tzpattern = ("^(:.*|" tzname offset "(" tzname \ "(" offset ")?(" datetime datetime ")?)?)$") exit tz ~ tzpattern } ' while echo >&2 'Please enter the desired value' \ 'of the TZ environment variable.' echo >&2 'For example, AEST-10 is abbreviated' \ 'AEST and is 10 hours' echo >&2 'ahead (east) of Greenwich,' \ 'with no daylight saving time.' read tz $AWK "$check_POSIX_TZ_string" ="$tz" do say >&2 "'$tz' is not a conforming POSIX.1-2017 timezone string." done TZ_for_date=$tz;; *) case $continent in coord) case $coord in '') echo >&2 'Please enter coordinates' \ 'in ISO 6709 notation.' echo >&2 'For example, +4042-07403 stands for' echo >&2 '40 degrees 42 minutes north,' \ '74 degrees 3 minutes west.' read coord esac distance_table=` $AWK \ "$output_distances_or_times" \ ="$coord" ="$TZ_COUNTRY_TABLE" ="$TZ_ZONE_TABLE" | sort -n | $AWK "{print} NR == $location_limit { exit }" ` regions=` $AWK ' BEGIN { distance_table = substr(ARGV[1], 2) ARGV[1] = "" nlines = split(distance_table, line, /\n/) for (nr = 1; nr <= nlines; nr++) { nf = split(line[nr], f, /\t/) print f[nf] } } ' ="$distance_table" ` echo >&2 'Please select one of the following timezones,' echo >&2 'listed roughly in increasing order' \ "of distance from $coord". doselect $regions region=$select_result tz=` $AWK ' BEGIN { distance_table = substr(ARGV[1], 2) region = substr(ARGV[2], 2) ARGV[1] = ARGV[2] = "" nlines = split(distance_table, line, /\n/) for (nr = 1; nr <= nlines; nr++) { nf = split(line[nr], f, /\t/) if (f[nf] == region) print f[4] } } ' ="$distance_table" ="$region" `;; *) case $continent in now|time) minute_format='%a %b %d %H:%M' old_minute=`TZ=UTC0 date +"$minute_format"` for i in 1 2 3 do time_table_command=` $AWK \ -v output_times=1 \ "$output_distances_or_times" \ = = ="$TZ_ZONE_TABLE" ` time_table=`eval "$time_table_command"` new_minute=`TZ=UTC0 date +"$minute_format"` case $old_minute in "$new_minute") break esac old_minute=$new_minute done echo >&2 "The system says Universal Time is $new_minute." echo >&2 "Assuming that's correct, what is the local time?" sorted_table=`say "$time_table" | sort -k2n -k2,5 -k1n` || { say >&2 "$0: cannot sort time table" exit 1 } eval doselect ` $AWK ' BEGIN { sorted_table = substr(ARGV[1], 2) ARGV[1] = "" nlines = split(sorted_table, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] outline = $6 " " $7 " " $4 " " $5 if (outline == oldline) continue oldline = outline gsub(/'\''/, "&\\\\&&", outline) printf "'\''%s'\''\n", outline } } ' ="$sorted_table" ` time=$select_result continent_re='^' zone_table=` $AWK ' BEGIN { time = substr(ARGV[1], 2) time_table = substr(ARGV[2], 2) ARGV[1] = ARGV[2] = "" nlines = split(time_table, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($6 " " $7 " " $4 " " $5 == time) { sub(/[^\t]*\t/, "") print } } } ' ="$time" ="$time_table" ` countries=` $AWK \ "$output_country_list" \ ="$continent_re" ="$TZ_COUNTRY_TABLE" ="$zone_table" | sort -f ` ;; *) continent_re="^$continent/" zone_table=$TZ_ZONE_TABLE esac # Get list of names of countries in the continent or ocean. countries=` $AWK \ "$output_country_list" \ ="$continent_re" ="$TZ_COUNTRY_TABLE" ="$zone_table" | sort -f ` # If all zone table entries have comments, and there are # at most 22 entries, asked based on those comments. # This fits the prompt onto old-fashioned 24-line screens. regions=` $AWK ' BEGIN { TZ_ZONE_TABLE = substr(ARGV[1], 2) ARGV[1] = "" FS = "\t" nlines = split(TZ_ZONE_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 ~ /^[^#]/ && !missing_comment) { if ($4) comment[++inlines] = $4 else missing_comment = 1 } } if (!missing_comment && inlines <= 22) for (i = 1; i <= inlines; i++) print comment[i] } ' ="$zone_table" ` # If there's more than one country, ask the user which one. case $countries in *"$newline"*) echo >&2 'Please select a country' \ 'whose clocks agree with yours.' doselect $countries country_result=$select_result country=$select_result;; *) country=$countries esac # Get list of timezones in the country. regions=` $AWK ' BEGIN { country = substr(ARGV[1], 2) TZ_COUNTRY_TABLE = substr(ARGV[2], 2) TZ_ZONE_TABLE = substr(ARGV[3], 2) ARGV[1] = ARGV[2] = ARGV[3] = "" FS = "\t" cc = country nlines = split(TZ_COUNTRY_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 !~ /^#/ && country == $2) { cc = $1 break } } nlines = split(TZ_ZONE_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 ~ /^#/) continue if ($1 ~ cc) print $4 } } ' ="$country" ="$TZ_COUNTRY_TABLE" ="$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 timezones.' doselect $regions region=$select_result esac # Determine tz from country and region. tz=` $AWK ' BEGIN { country = substr(ARGV[1], 2) region = substr(ARGV[2], 2) TZ_COUNTRY_TABLE = substr(ARGV[3], 2) TZ_ZONE_TABLE = substr(ARGV[4], 2) ARGV[1] = ARGV[2] = ARGV[3] = ARGV[4] = "" FS = "\t" cc = country nlines = split(TZ_COUNTRY_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 !~ /^#/ && country == $2) { cc = $1 break } } nlines = split(TZ_ZONE_TABLE, line, /\n/) for (i = 1; i <= nlines; i++) { $0 = line[i] if ($0 ~ /^#/) continue if ($1 ~ cc && ($4 == region || !region)) print $3 } } ' ="$country" ="$region" ="$TZ_COUNTRY_TABLE" ="$zone_table" ` esac # Make sure the corresponding zoneinfo file exists. TZ_for_date=$TZDIR/$tz <"$TZ_for_date" || { say >&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` if $AWK ' function getsecs(d) { return match(d, /.*:[0-5][0-9]/) ? substr(d, RLENGTH - 1, 2) : "" } BEGIN { exit getsecs(ARGV[1]) != getsecs(ARGV[2]) } ' ="$TZdate" ="$UTdate" then extra_info=" Selected time is now: $TZdate. Universal Time is now: $UTdate." break fi done # Output TZ info and ask the user to confirm. echo >&2 "" echo >&2 "Based on the following information:" echo >&2 "" case $time%$country_result%$region%$coord in ?*%?*%?*%) say >&2 " $time$newline $country_result$newline $region";; ?*%?*%%|?*%%?*%) say >&2 " $time$newline $country_result$region";; ?*%%%) say >&2 " $time";; %?*%?*%) say >&2 " $country_result$newline $region";; %?*%%) say >&2 " $country_result";; %%?*%?*) say >&2 " coord $coord$newline $region";; %%%?*) say >&2 " coord $coord";; *) say >&2 " TZ='$tz'" esac say >&2 "" say >&2 "TZ='$tz' will be used.$extra_info" say >&2 "Is the above information OK?" doselect Yes No ok=$select_result case $ok in Yes) break esac do coord= done case $SHELL in *csh) file=.login line="setenv TZ '$tz'";; *) file=.profile line="TZ='$tz'; export TZ" esac test -t 1 && say >&2 " You can make this change permanent for yourself by appending the line $line to the file '$file' in your home directory; then log out and log in again. Here is that TZ value again, this time on standard output so that you can use the $0 command in shell scripts:" say "$tz"