1#! /bin/bash 2# 3# Ask the user about the time zone, and output the resulting TZ value to stdout. 4# Interact with the user via stderr and stdin. 5# 6# $NetBSD: tzselect.ksh,v 1.18 2018/10/19 23:05:35 christos Exp $ 7# 8PKGVERSION='(tzcode) ' 9TZVERSION=see_Makefile 10REPORT_BUGS_TO=tz@iana.org 11 12# Contributed by Paul Eggert. This file is in the public domain. 13 14# Porting notes: 15# 16# This script requires a Posix-like shell and prefers the extension of a 17# 'select' statement. The 'select' statement was introduced in the 18# Korn shell and is available in Bash and other shell implementations. 19# If your host lacks both Bash and the Korn shell, you can get their 20# source from one of these locations: 21# 22# Bash <https://www.gnu.org/software/bash/> 23# Korn Shell <http://www.kornshell.com/> 24# MirBSD Korn Shell <https://www.mirbsd.org/mksh.htm> 25# 26# For portability to Solaris 9 /bin/sh this script avoids some POSIX 27# features and common extensions, such as $(...) (which works sometimes 28# but not others), $((...)), and $10. 29# 30# This script also uses several features of modern awk programs. 31# If your host lacks awk, or has an old awk that does not conform to Posix, 32# you can use either of the following free programs instead: 33# 34# Gawk (GNU awk) <https://www.gnu.org/software/gawk/> 35# mawk <https://invisible-island.net/mawk/> 36 37 38# Specify default values for environment variables if they are unset. 39: ${AWK=awk} 40: ${TZDIR=`pwd`} 41 42# Output one argument as-is to standard output. 43# Safer than 'echo', which can mishandle '\' or leading '-'. 44say() { 45 printf '%s\n' "$1" 46} 47 48# Check for awk Posix compliance. 49($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1 50[ $? = 123 ] || { 51 say >&2 "$0: Sorry, your '$AWK' program is not Posix compatible." 52 exit 1 53} 54 55coord= 56location_limit=10 57zonetabtype=zone1970 58 59usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT] 60Select a timezone interactively. 61 62Options: 63 64 -c COORD 65 Instead of asking for continent and then country and then city, 66 ask for selection from time zones whose largest cities 67 are closest to the location with geographical coordinates COORD. 68 COORD should use ISO 6709 notation, for example, '-c +4852+00220' 69 for Paris (in degrees and minutes, North and East), or 70 '-c -35-058' for Buenos Aires (in degrees, South and West). 71 72 -n LIMIT 73 Display at most LIMIT locations when -c is used (default $location_limit). 74 75 --version 76 Output version information. 77 78 --help 79 Output this help. 80 81Report bugs to $REPORT_BUGS_TO." 82 83# Ask the user to select from the function's arguments, 84# and assign the selected argument to the variable 'select_result'. 85# Exit on EOF or I/O error. Use the shell's 'select' builtin if available, 86# falling back on a less-nice but portable substitute otherwise. 87if 88 case $BASH_VERSION in 89 ?*) : ;; 90 '') 91 # '; exit' should be redundant, but Dash doesn't properly fail without it. 92 (eval 'set --; select x; do break; done; exit') </dev/null 2>/dev/null 93 esac 94then 95 # Do this inside 'eval', as otherwise the shell might exit when parsing it 96 # even though it is never executed. 97 eval ' 98 doselect() { 99 select select_result 100 do 101 case $select_result in 102 "") echo >&2 "Please enter a number in range." ;; 103 ?*) break 104 esac 105 done || exit 106 } 107 108 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout. 109 case $BASH_VERSION in 110 [01].*) 111 case `echo 1 | (select x in x; do break; done) 2>/dev/null` in 112 ?*) PS3= 113 esac 114 esac 115 ' 116else 117 doselect() { 118 # Field width of the prompt numbers. 119 select_width=`expr $# : '.*'` 120 121 select_i= 122 123 while : 124 do 125 case $select_i in 126 '') 127 select_i=0 128 for select_word 129 do 130 select_i=`expr $select_i + 1` 131 printf >&2 "%${select_width}d) %s\\n" $select_i "$select_word" 132 done ;; 133 *[!0-9]*) 134 echo >&2 'Please enter a number in range.' ;; 135 *) 136 if test 1 -le $select_i && test $select_i -le $#; then 137 shift `expr $select_i - 1` 138 select_result=$1 139 break 140 fi 141 echo >&2 'Please enter a number in range.' 142 esac 143 144 # Prompt and read input. 145 printf >&2 %s "${PS3-#? }" 146 read select_i || exit 147 done 148 } 149fi 150 151while getopts c:n:t:-: opt 152do 153 case $opt$OPTARG in 154 c*) 155 coord=$OPTARG ;; 156 n*) 157 location_limit=$OPTARG ;; 158 t*) # Undocumented option, used for developer testing. 159 zonetabtype=$OPTARG ;; 160 -help) 161 exec echo "$usage" ;; 162 -version) 163 exec echo "tzselect $PKGVERSION$TZVERSION" ;; 164 -*) 165 say >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1 ;; 166 *) 167 say >&2 "$0: try '$0 --help'"; exit 1 ;; 168 esac 169done 170 171shift `expr $OPTIND - 1` 172case $# in 1730) ;; 174*) say >&2 "$0: $1: unknown argument"; exit 1 ;; 175esac 176 177# Make sure the tables are readable. 178TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab 179TZ_ZONE_TABLE=$TZDIR/$zonetabtype.tab 180for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE 181do 182 <"$f" || { 183 say >&2 "$0: time zone files are not set up correctly" 184 exit 1 185 } 186done 187 188# If the current locale does not support UTF-8, convert data to current 189# locale's format if possible, as the shell aligns columns better that way. 190# Check the UTF-8 of U+12345 CUNEIFORM SIGN URU TIMES KI. 191! $AWK 'BEGIN { u12345 = "\360\222\215\205"; exit length(u12345) != 1 }' && 192 { tmp=`(mktemp -d) 2>/dev/null` || { 193 tmp=${TMPDIR-/tmp}/tzselect.$$ && 194 (umask 77 && mkdir -- "$tmp") 195 };} && 196 trap 'status=$?; rm -fr -- "$tmp"; exit $status' 0 HUP INT PIPE TERM && 197 (iconv -f UTF-8 -t //TRANSLIT <"$TZ_COUNTRY_TABLE" >$tmp/iso3166.tab) \ 198 2>/dev/null && 199 TZ_COUNTRY_TABLE=$tmp/iso3166.tab && 200 iconv -f UTF-8 -t //TRANSLIT <"$TZ_ZONE_TABLE" >$tmp/$zonetabtype.tab && 201 TZ_ZONE_TABLE=$tmp/$zonetabtype.tab 202 203newline=' 204' 205IFS=$newline 206 207 208# Awk script to read a time zone table and output the same table, 209# with each column preceded by its distance from 'here'. 210output_distances=' 211 BEGIN { 212 FS = "\t" 213 while (getline <TZ_COUNTRY_TABLE) 214 if ($0 ~ /^[^#]/) 215 country[$1] = $2 216 country["US"] = "US" # Otherwise the strings get too long. 217 } 218 function abs(x) { 219 return x < 0 ? -x : x; 220 } 221 function min(x, y) { 222 return x < y ? x : y; 223 } 224 function convert_coord(coord, deg, minute, ilen, sign, sec) { 225 if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9][0-9][0-9]([^0-9]|$)/) { 226 degminsec = coord 227 intdeg = degminsec < 0 ? -int(-degminsec / 10000) : int(degminsec / 10000) 228 minsec = degminsec - intdeg * 10000 229 intmin = minsec < 0 ? -int(-minsec / 100) : int(minsec / 100) 230 sec = minsec - intmin * 100 231 deg = (intdeg * 3600 + intmin * 60 + sec) / 3600 232 } else if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9]([^0-9]|$)/) { 233 degmin = coord 234 intdeg = degmin < 0 ? -int(-degmin / 100) : int(degmin / 100) 235 minute = degmin - intdeg * 100 236 deg = (intdeg * 60 + minute) / 60 237 } else 238 deg = coord 239 return deg * 0.017453292519943296 240 } 241 function convert_latitude(coord) { 242 match(coord, /..*[-+]/) 243 return convert_coord(substr(coord, 1, RLENGTH - 1)) 244 } 245 function convert_longitude(coord) { 246 match(coord, /..*[-+]/) 247 return convert_coord(substr(coord, RLENGTH)) 248 } 249 # Great-circle distance between points with given latitude and longitude. 250 # Inputs and output are in radians. This uses the great-circle special 251 # case of the Vicenty formula for distances on ellipsoids. 252 function gcdist(lat1, long1, lat2, long2, dlong, x, y, num, denom) { 253 dlong = long2 - long1 254 x = cos(lat2) * sin(dlong) 255 y = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dlong) 256 num = sqrt(x * x + y * y) 257 denom = sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(dlong) 258 return atan2(num, denom) 259 } 260 # Parallel distance between points with given latitude and longitude. 261 # This is the product of the longitude difference and the cosine 262 # of the latitude of the point that is further from the equator. 263 # I.e., it considers longitudes to be further apart if they are 264 # nearer the equator. 265 function pardist(lat1, long1, lat2, long2) { 266 return abs(long1 - long2) * min(cos(lat1), cos(lat2)) 267 } 268 # The distance function is the sum of the great-circle distance and 269 # the parallel distance. It could be weighted. 270 function dist(lat1, long1, lat2, long2) { 271 return gcdist(lat1, long1, lat2, long2) + pardist(lat1, long1, lat2, long2) 272 } 273 BEGIN { 274 coord_lat = convert_latitude(coord) 275 coord_long = convert_longitude(coord) 276 } 277 /^[^#]/ { 278 here_lat = convert_latitude($2) 279 here_long = convert_longitude($2) 280 line = $1 "\t" $2 "\t" $3 281 sep = "\t" 282 ncc = split($1, cc, /,/) 283 for (i = 1; i <= ncc; i++) { 284 line = line sep country[cc[i]] 285 sep = ", " 286 } 287 if (NF == 4) 288 line = line " - " $4 289 printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), line 290 } 291' 292 293# Begin the main loop. We come back here if the user wants to retry. 294while 295 296 echo >&2 'Please identify a location' \ 297 'so that time zone rules can be set correctly.' 298 299 continent= 300 country= 301 region= 302 303 case $coord in 304 ?*) 305 continent=coord;; 306 '') 307 308 # Ask the user for continent or ocean. 309 310 echo >&2 'Please select a continent, ocean, "coord", or "TZ".' 311 312 quoted_continents=` 313 $AWK ' 314 BEGIN { FS = "\t" } 315 /^[^#]/ { 316 entry = substr($3, 1, index($3, "/") - 1) 317 if (entry == "America") 318 entry = entry "s" 319 if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/) 320 entry = entry " Ocean" 321 printf "'\''%s'\''\n", entry 322 } 323 ' <"$TZ_ZONE_TABLE" | 324 sort -u | 325 tr '\n' ' ' 326 echo '' 327 ` 328 329 eval ' 330 doselect '"$quoted_continents"' \ 331 "coord - I want to use geographical coordinates." \ 332 "TZ - I want to specify the timezone using the Posix TZ format." 333 continent=$select_result 334 case $continent in 335 Americas) continent=America;; 336 *" "*) continent=`expr "$continent" : '\''\([^ ]*\)'\''` 337 esac 338 ' 339 esac 340 341 case $continent in 342 TZ) 343 # Ask the user for a Posix TZ string. Check that it conforms. 344 while 345 echo >&2 'Please enter the desired value' \ 346 'of the TZ environment variable.' 347 echo >&2 'For example, AEST-10 is abbreviated' \ 348 'AEST and is 10 hours' 349 echo >&2 'ahead (east) of Greenwich,' \ 350 'with no daylight saving time.' 351 read TZ 352 $AWK -v TZ="$TZ" 'BEGIN { 353 tzname = "(<[[:alnum:]+-]{3,}>|[[:alpha:]]{3,})" 354 time = "(2[0-4]|[0-1]?[0-9])" \ 355 "(:[0-5][0-9](:[0-5][0-9])?)?" 356 offset = "[-+]?" time 357 mdate = "M([1-9]|1[0-2])\\.[1-5]\\.[0-6]" 358 jdate = "((J[1-9]|[0-9]|J?[1-9][0-9]" \ 359 "|J?[1-2][0-9][0-9])|J?3[0-5][0-9]|J?36[0-5])" 360 datetime = ",(" mdate "|" jdate ")(/" time ")?" 361 tzpattern = "^(:.*|" tzname offset "(" tzname \ 362 "(" offset ")?(" datetime datetime ")?)?)$" 363 if (TZ ~ tzpattern) exit 1 364 exit 0 365 }' 366 do 367 say >&2 "'$TZ' is not a conforming Posix timezone string." 368 done 369 TZ_for_date=$TZ;; 370 *) 371 case $continent in 372 coord) 373 case $coord in 374 '') 375 echo >&2 'Please enter coordinates' \ 376 'in ISO 6709 notation.' 377 echo >&2 'For example, +4042-07403 stands for' 378 echo >&2 '40 degrees 42 minutes north,' \ 379 '74 degrees 3 minutes west.' 380 read coord;; 381 esac 382 distance_table=`$AWK \ 383 -v coord="$coord" \ 384 -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ 385 "$output_distances" <"$TZ_ZONE_TABLE" | 386 sort -n | 387 sed "${location_limit}q" 388 ` 389 regions=`say "$distance_table" | $AWK ' 390 BEGIN { FS = "\t" } 391 { print $NF } 392 '` 393 echo >&2 'Please select one of the following timezones,' \ 394 echo >&2 'listed roughly in increasing order' \ 395 "of distance from $coord". 396 doselect $regions 397 region=$select_result 398 TZ=`say "$distance_table" | $AWK -v region="$region" ' 399 BEGIN { FS="\t" } 400 $NF == region { print $4 } 401 '` 402 ;; 403 *) 404 # Get list of names of countries in the continent or ocean. 405 countries=`$AWK \ 406 -v continent="$continent" \ 407 -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ 408 ' 409 BEGIN { FS = "\t" } 410 /^#/ { next } 411 $3 ~ ("^" continent "/") { 412 ncc = split($1, cc, /,/) 413 for (i = 1; i <= ncc; i++) 414 if (!cc_seen[cc[i]]++) cc_list[++ccs] = cc[i] 415 } 416 END { 417 while (getline <TZ_COUNTRY_TABLE) { 418 if ($0 !~ /^#/) cc_name[$1] = $2 419 } 420 for (i = 1; i <= ccs; i++) { 421 country = cc_list[i] 422 if (cc_name[country]) { 423 country = cc_name[country] 424 } 425 print country 426 } 427 } 428 ' <"$TZ_ZONE_TABLE" | sort -f` 429 430 431 # If there's more than one country, ask the user which one. 432 case $countries in 433 *"$newline"*) 434 echo >&2 'Please select a country' \ 435 'whose clocks agree with yours.' 436 doselect $countries 437 country=$select_result;; 438 *) 439 country=$countries 440 esac 441 442 443 # Get list of timezones in the country. 444 regions=`$AWK \ 445 -v country="$country" \ 446 -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ 447 ' 448 BEGIN { 449 FS = "\t" 450 cc = country 451 while (getline <TZ_COUNTRY_TABLE) { 452 if ($0 !~ /^#/ && country == $2) { 453 cc = $1 454 break 455 } 456 } 457 } 458 /^#/ { next } 459 $1 ~ cc { print $4 } 460 ' <"$TZ_ZONE_TABLE"` 461 462 463 # If there's more than one region, ask the user which one. 464 case $regions in 465 *"$newline"*) 466 echo >&2 'Please select one of the following timezones.' 467 doselect $regions 468 region=$select_result;; 469 *) 470 region=$regions 471 esac 472 473 # Determine TZ from country and region. 474 TZ=`$AWK \ 475 -v country="$country" \ 476 -v region="$region" \ 477 -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \ 478 ' 479 BEGIN { 480 FS = "\t" 481 cc = country 482 while (getline <TZ_COUNTRY_TABLE) { 483 if ($0 !~ /^#/ && country == $2) { 484 cc = $1 485 break 486 } 487 } 488 } 489 /^#/ { next } 490 $1 ~ cc && $4 == region { print $3 } 491 ' <"$TZ_ZONE_TABLE"` 492 esac 493 494 # Make sure the corresponding zoneinfo file exists. 495 TZ_for_date=$TZDIR/$TZ 496 <"$TZ_for_date" || { 497 say >&2 "$0: time zone files are not set up correctly" 498 exit 1 499 } 500 esac 501 502 503 # Use the proposed TZ to output the current date relative to UTC. 504 # Loop until they agree in seconds. 505 # Give up after 8 unsuccessful tries. 506 507 extra_info= 508 for i in 1 2 3 4 5 6 7 8 509 do 510 TZdate=`LANG=C TZ="$TZ_for_date" date` 511 UTdate=`LANG=C TZ=UTC0 date` 512 TZsec=`expr "$TZdate" : '.*:\([0-5][0-9]\)'` 513 UTsec=`expr "$UTdate" : '.*:\([0-5][0-9]\)'` 514 case $TZsec in 515 $UTsec) 516 extra_info=" 517Selected time is now: $TZdate. 518Universal Time is now: $UTdate." 519 break 520 esac 521 done 522 523 524 # Output TZ info and ask the user to confirm. 525 526 echo >&2 "" 527 echo >&2 "The following information has been given:" 528 echo >&2 "" 529 case $country%$region%$coord in 530 ?*%?*%) say >&2 " $country$newline $region";; 531 ?*%%) say >&2 " $country";; 532 %?*%?*) say >&2 " coord $coord$newline $region";; 533 %%?*) say >&2 " coord $coord";; 534 *) say >&2 " TZ='$TZ'" 535 esac 536 say >&2 "" 537 say >&2 "Therefore TZ='$TZ' will be used.$extra_info" 538 say >&2 "Is the above information OK?" 539 540 doselect Yes No 541 ok=$select_result 542 case $ok in 543 Yes) break 544 esac 545do coord= 546done 547 548case $SHELL in 549*csh) file=.login line="setenv TZ '$TZ'";; 550*) file=.profile line="TZ='$TZ'; export TZ" 551esac 552 553test -t 1 && say >&2 " 554You can make this change permanent for yourself by appending the line 555 $line 556to the file '$file' in your home directory; then log out and log in again. 557 558Here is that TZ value again, this time on standard output so that you 559can use the $0 command in shell scripts:" 560 561say "$TZ" 562