timezone/tzselect.ksh

   1 #!/bin/bash
   2 # Ask the user about the time zone, and output the resulting TZ value to stdout.
   3 # Interact with the user via stderr and stdin.
   4
   5 PKGVERSION='(tzcode) '
   6 TZVERSION=see_Makefile
   7 REPORT_BUGS_TO=tz@iana.org
   8
   9 # Contributed by Paul Eggert.  This file is in the public domain.
  10
  11 # Porting notes:
  12 #
  13 # This script requires a Posix-like shell and prefers the extension of a
  14 # 'select' statement.  The 'select' statement was introduced in the
  15 # Korn shell and is available in Bash and other shell implementations.
  16 # If your host lacks both Bash and the Korn shell, you can get their
  17 # source from one of these locations:
  18 #
  19 #       Bash <https://www.gnu.org/software/bash/>
  20 #       Korn Shell <http://www.kornshell.com/>
  21 #       MirBSD Korn Shell <https://www.mirbsd.org/mksh.htm>
  22 #
  23 # For portability to Solaris 9 /bin/sh this script avoids some POSIX
  24 # features and common extensions, such as $(...) (which works sometimes
  25 # but not others), $((...)), and $10.
  26 #
  27 # This script also uses several features of modern awk programs.
  28 # If your host lacks awk, or has an old awk that does not conform to Posix,
  29 # you can use either of the following free programs instead:
  30 #
  31 #       Gawk (GNU awk) <https://www.gnu.org/software/gawk/>
  32 #       mawk <https://invisible-island.net/mawk/>
  33
  34
  35 # Specify default values for environment variables if they are unset.
  36 : ${AWK=awk}
  37 : ${TZDIR=`pwd`}
  38
  39 # Output one argument as-is to standard output.
  40 # Safer than 'echo', which can mishandle '\' or leading '-'.
  41 say() {
  42     printf '%s\n' "$1"
  43 }
  44
  45 # Check for awk Posix compliance.
  46 ($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
  47 [ $? = 123 ] || {
  48         say >&2 "$0: Sorry, your '$AWK' program is not Posix compatible."
  49         exit 1
  50 }
  51
  52 coord=
  53 location_limit=10
  54 zonetabtype=zone1970
  55
  56 usage="Usage: tzselect [--version] [--help] [-c COORD] [-n LIMIT]
  57 Select a timezone interactively.
  58
  59 Options:
  60
  61   -c COORD
  62     Instead of asking for continent and then country and then city,
  63     ask for selection from time zones whose largest cities
  64     are closest to the location with geographical coordinates COORD.
  65     COORD should use ISO 6709 notation, for example, '-c +4852+00220'
  66     for Paris (in degrees and minutes, North and East), or
  67     '-c -35-058' for Buenos Aires (in degrees, South and West).
  68
  69   -n LIMIT
  70     Display at most LIMIT locations when -c is used (default $location_limit).
  71
  72   --version
  73     Output version information.
  74
  75   --help
  76     Output this help.
  77
  78 Report bugs to $REPORT_BUGS_TO."
  79
  80 # Ask the user to select from the function's arguments,
  81 # and assign the selected argument to the variable 'select_result'.
  82 # Exit on EOF or I/O error.  Use the shell's 'select' builtin if available,
  83 # falling back on a less-nice but portable substitute otherwise.
  84 if
  85   case $BASH_VERSION in
  86   ?*) : ;;
  87   '')
  88     # '; exit' should be redundant, but Dash doesn't properly fail without it.
  89     (eval 'set --; select x; do break; done; exit') </dev/null 2>/dev/null
  90   esac
  91 then
  92   # Do this inside 'eval', as otherwise the shell might exit when parsing it
  93   # even though it is never executed.
  94   eval '
  95     doselect() {
  96       select select_result
  97       do
  98         case $select_result in
  99         "") echo >&2 "Please enter a number in range." ;;
 100         ?*) break
 101         esac
 102       done || exit
 103     }
 104
 105     # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
 106     case $BASH_VERSION in
 107     [01].*)
 108       case `echo 1 | (select x in x; do break; done) 2>/dev/null` in
 109       ?*) PS3=
 110       esac
 111     esac
 112   '
 113 else
 114   doselect() {
 115     # Field width of the prompt numbers.
 116     select_width=`expr $# : '.*'`
 117
 118     select_i=
 119
 120     while :
 121     do
 122       case $select_i in
 123       '')
 124         select_i=0
 125         for select_word
 126         do
 127           select_i=`expr $select_i + 1`
 128           printf >&2 "%${select_width}d) %s\\n" $select_i "$select_word"
 129         done ;;
 130       *[!0-9]*)
 131         echo >&2 'Please enter a number in range.' ;;
 132       *)
 133         if test 1 -le $select_i && test $select_i -le $#; then
 134           shift `expr $select_i - 1`
 135           select_result=$1
 136           break
 137         fi
 138         echo >&2 'Please enter a number in range.'
 139       esac
 140
 141       # Prompt and read input.
 142       printf >&2 %s "${PS3-#? }"
 143       read select_i || exit
 144     done
 145   }
 146 fi
 147
 148 while getopts c:n:t:-: opt
 149 do
 150     case $opt$OPTARG in
 151     c*)
 152         coord=$OPTARG ;;
 153     n*)
 154         location_limit=$OPTARG ;;
 155     t*) # Undocumented option, used for developer testing.
 156         zonetabtype=$OPTARG ;;
 157     -help)
 158         exec echo "$usage" ;;
 159     -version)
 160         exec echo "tzselect $PKGVERSION$TZVERSION" ;;
 161     -*)
 162         say >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1 ;;
 163     *)
 164         say >&2 "$0: try '$0 --help'"; exit 1 ;;
 165     esac
 166 done
 167
 168 shift `expr $OPTIND - 1`
 169 case $# in
 170 0) ;;
 171 *) say >&2 "$0: $1: unknown argument"; exit 1 ;;
 172 esac
 173
 174 # Make sure the tables are readable.
 175 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
 176 TZ_ZONE_TABLE=$TZDIR/$zonetabtype.tab
 177 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
 178 do
 179         <"$f" || {
 180                 say >&2 "$0: time zone files are not set up correctly"
 181                 exit 1
 182         }
 183 done
 184
 185 # If the current locale does not support UTF-8, convert data to current
 186 # locale's format if possible, as the shell aligns columns better that way.
 187 # Check the UTF-8 of U+12345 CUNEIFORM SIGN URU TIMES KI.
 188 ! $AWK 'BEGIN { u12345 = "\360\222\215\205"; exit length(u12345) != 1 }' &&
 189     { tmp=`(mktemp -d) 2>/dev/null` || {
 190         tmp=${TMPDIR-/tmp}/tzselect.$$ &&
 191         (umask 77 && mkdir -- "$tmp")
 192     };} &&
 193     trap 'status=$?; rm -fr -- "$tmp"; exit $status' 0 HUP INT PIPE TERM &&
 194     (iconv -f UTF-8 -t //TRANSLIT <"$TZ_COUNTRY_TABLE" >$tmp/iso3166.tab) \
 195         2>/dev/null &&
 196     TZ_COUNTRY_TABLE=$tmp/iso3166.tab &&
 197     iconv -f UTF-8 -t //TRANSLIT <"$TZ_ZONE_TABLE" >$tmp/$zonetabtype.tab &&
 198     TZ_ZONE_TABLE=$tmp/$zonetabtype.tab
 199
 200 newline='
 201 '
 202 IFS=$newline
 203
 204
 205 # Awk script to read a time zone table and output the same table,
 206 # with each column preceded by its distance from 'here'.
 207 output_distances='
 208   BEGIN {
 209     FS = "\t"
 210     while (getline <TZ_COUNTRY_TABLE)
 211       if ($0 ~ /^[^#]/)
 212         country[$1] = $2
 213     country["US"] = "US" # Otherwise the strings get too long.
 214   }
 215   function abs(x) {
 216     return x < 0 ? -x : x;
 217   }
 218   function min(x, y) {
 219     return x < y ? x : y;
 220   }
 221   function convert_coord(coord, deg, minute, ilen, sign, sec) {
 222     if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9][0-9][0-9]([^0-9]|$)/) {
 223       degminsec = coord
 224       intdeg = degminsec < 0 ? -int(-degminsec / 10000) : int(degminsec / 10000)
 225       minsec = degminsec - intdeg * 10000
 226       intmin = minsec < 0 ? -int(-minsec / 100) : int(minsec / 100)
 227       sec = minsec - intmin * 100
 228       deg = (intdeg * 3600 + intmin * 60 + sec) / 3600
 229     } else if (coord ~ /^[-+]?[0-9]?[0-9][0-9][0-9][0-9]([^0-9]|$)/) {
 230       degmin = coord
 231       intdeg = degmin < 0 ? -int(-degmin / 100) : int(degmin / 100)
 232       minute = degmin - intdeg * 100
 233       deg = (intdeg * 60 + minute) / 60
 234     } else
 235       deg = coord
 236     return deg * 0.017453292519943296
 237   }
 238   function convert_latitude(coord) {
 239     match(coord, /..*[-+]/)
 240     return convert_coord(substr(coord, 1, RLENGTH - 1))
 241   }
 242   function convert_longitude(coord) {
 243     match(coord, /..*[-+]/)
 244     return convert_coord(substr(coord, RLENGTH))
 245   }
 246   # Great-circle distance between points with given latitude and longitude.
 247   # Inputs and output are in radians.  This uses the great-circle special
 248   # case of the Vicenty formula for distances on ellipsoids.
 249   function gcdist(lat1, long1, lat2, long2, dlong, x, y, num, denom) {
 250     dlong = long2 - long1
 251     x = cos(lat2) * sin(dlong)
 252     y = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dlong)
 253     num = sqrt(x * x + y * y)
 254     denom = sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(dlong)
 255     return atan2(num, denom)
 256   }
 257   # Parallel distance between points with given latitude and longitude.
 258   # This is the product of the longitude difference and the cosine
 259   # of the latitude of the point that is further from the equator.
 260   # I.e., it considers longitudes to be further apart if they are
 261   # nearer the equator.
 262   function pardist(lat1, long1, lat2, long2) {
 263     return abs(long1 - long2) * min(cos(lat1), cos(lat2))
 264   }
 265   # The distance function is the sum of the great-circle distance and
 266   # the parallel distance.  It could be weighted.
 267   function dist(lat1, long1, lat2, long2) {
 268     return gcdist(lat1, long1, lat2, long2) + pardist(lat1, long1, lat2, long2)
 269   }
 270   BEGIN {
 271     coord_lat = convert_latitude(coord)
 272     coord_long = convert_longitude(coord)
 273   }
 274   /^[^#]/ {
 275     here_lat = convert_latitude($2)
 276     here_long = convert_longitude($2)
 277     line = $1 "\t" $2 "\t" $3
 278     sep = "\t"
 279     ncc = split($1, cc, /,/)
 280     for (i = 1; i <= ncc; i++) {
 281       line = line sep country[cc[i]]
 282       sep = ", "
 283     }
 284     if (NF == 4)
 285       line = line " - " $4
 286     printf "%g\t%s\n", dist(coord_lat, coord_long, here_lat, here_long), line
 287   }
 288 '
 289
 290 # Begin the main loop.  We come back here if the user wants to retry.
 291 while
 292
 293         echo >&2 'Please identify a location' \
 294                 'so that time zone rules can be set correctly.'
 295
 296         continent=
 297         country=
 298         region=
 299
 300         case $coord in
 301         ?*)
 302                 continent=coord;;
 303         '')
 304
 305         # Ask the user for continent or ocean.
 306
 307         echo >&2 'Please select a continent, ocean, "coord", or "TZ".'
 308
 309         quoted_continents=`
 310           $AWK '
 311             BEGIN { FS = "\t" }
 312             /^[^#]/ {
 313               entry = substr($3, 1, index($3, "/") - 1)
 314               if (entry == "America")
 315                 entry = entry "s"
 316               if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/)
 317                 entry = entry " Ocean"
 318               printf "'\''%s'\''\n", entry
 319             }
 320           ' <"$TZ_ZONE_TABLE" |
 321           sort -u |
 322           tr '\n' ' '
 323           echo ''
 324         `
 325
 326         eval '
 327             doselect '"$quoted_continents"' \
 328                 "coord - I want to use geographical coordinates." \
 329                 "TZ - I want to specify the timezone using the Posix TZ format."
 330             continent=$select_result
 331             case $continent in
 332             Americas) continent=America;;
 333             *" "*) continent=`expr "$continent" : '\''\([^ ]*\)'\''`
 334             esac
 335         '
 336         esac
 337
 338         case $continent in
 339         TZ)
 340                 # Ask the user for a Posix TZ string.  Check that it conforms.
 341                 while
 342                         echo >&2 'Please enter the desired value' \
 343                                 'of the TZ environment variable.'
 344                         echo >&2 'For example, AEST-10 is abbreviated' \
 345                                 'AEST and is 10 hours'
 346                         echo >&2 'ahead (east) of Greenwich,' \
 347                                 'with no daylight saving time.'
 348                         read TZ
 349                         $AWK -v TZ="$TZ" 'BEGIN {
 350                                 tzname = "(<[[:alnum:]+-]{3,}>|[[:alpha:]]{3,})"
 351                                 time = "(2[0-4]|[0-1]?[0-9])" \
 352                                   "(:[0-5][0-9](:[0-5][0-9])?)?"
 353                                 offset = "[-+]?" time
 354                                 mdate = "M([1-9]|1[0-2])\\.[1-5]\\.[0-6]"
 355                                 jdate = "((J[1-9]|[0-9]|J?[1-9][0-9]" \
 356                                   "|J?[1-2][0-9][0-9])|J?3[0-5][0-9]|J?36[0-5])"
 357                                 datetime = ",(" mdate "|" jdate ")(/" time ")?"
 358                                 tzpattern = "^(:.*|" tzname offset "(" tzname \
 359                                   "(" offset ")?(" datetime datetime ")?)?)$"
 360                                 if (TZ ~ tzpattern) exit 1
 361                                 exit 0
 362                         }'
 363                 do
 364                     say >&2 "'$TZ' is not a conforming Posix timezone string."
 365                 done
 366                 TZ_for_date=$TZ;;
 367         *)
 368                 case $continent in
 369                 coord)
 370                     case $coord in
 371                     '')
 372                         echo >&2 'Please enter coordinates' \
 373                                 'in ISO 6709 notation.'
 374                         echo >&2 'For example, +4042-07403 stands for'
 375                         echo >&2 '40 degrees 42 minutes north,' \
 376                                 '74 degrees 3 minutes west.'
 377                         read coord;;
 378                     esac
 379                     distance_table=`$AWK \
 380                             -v coord="$coord" \
 381                             -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 382                             "$output_distances" <"$TZ_ZONE_TABLE" |
 383                       sort -n |
 384                       sed "${location_limit}q"
 385                     `
 386                     regions=`say "$distance_table" | $AWK '
 387                       BEGIN { FS = "\t" }
 388                       { print $NF }
 389                     '`
 390                     echo >&2 'Please select one of the following timezones,' \
 391                     echo >&2 'listed roughly in increasing order' \
 392                             "of distance from $coord".
 393                     doselect $regions
 394                     region=$select_result
 395                     TZ=`say "$distance_table" | $AWK -v region="$region" '
 396                       BEGIN { FS="\t" }
 397                       $NF == region { print $4 }
 398                     '`
 399                     ;;
 400                 *)
 401                 # Get list of names of countries in the continent or ocean.
 402                 countries=`$AWK \
 403                         -v continent="$continent" \
 404                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 405                 '
 406                         BEGIN { FS = "\t" }
 407                         /^#/ { next }
 408                         $3 ~ ("^" continent "/") {
 409                             ncc = split($1, cc, /,/)
 410                             for (i = 1; i <= ncc; i++)
 411                                 if (!cc_seen[cc[i]]++) cc_list[++ccs] = cc[i]
 412                         }
 413                         END {
 414                                 while (getline <TZ_COUNTRY_TABLE) {
 415                                         if ($0 !~ /^#/) cc_name[$1] = $2
 416                                 }
 417                                 for (i = 1; i <= ccs; i++) {
 418                                         country = cc_list[i]
 419                                         if (cc_name[country]) {
 420                                           country = cc_name[country]
 421                                         }
 422                                         print country
 423                                 }
 424                         }
 425                 ' <"$TZ_ZONE_TABLE" | sort -f`
 426
 427
 428                 # If there's more than one country, ask the user which one.
 429                 case $countries in
 430                 *"$newline"*)
 431                         echo >&2 'Please select a country' \
 432                                 'whose clocks agree with yours.'
 433                         doselect $countries
 434                         country=$select_result;;
 435                 *)
 436                         country=$countries
 437                 esac
 438
 439
 440                 # Get list of timezones in the country.
 441                 regions=`$AWK \
 442                         -v country="$country" \
 443                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 444                 '
 445                         BEGIN {
 446                                 FS = "\t"
 447                                 cc = country
 448                                 while (getline <TZ_COUNTRY_TABLE) {
 449                                         if ($0 !~ /^#/  &&  country == $2) {
 450                                                 cc = $1
 451                                                 break
 452                                         }
 453                                 }
 454                         }
 455                         /^#/ { next }
 456                         $1 ~ cc { print $4 }
 457                 ' <"$TZ_ZONE_TABLE"`
 458
 459
 460                 # If there's more than one region, ask the user which one.
 461                 case $regions in
 462                 *"$newline"*)
 463                         echo >&2 'Please select one of the following timezones.'
 464                         doselect $regions
 465                         region=$select_result;;
 466                 *)
 467                         region=$regions
 468                 esac
 469
 470                 # Determine TZ from country and region.
 471                 TZ=`$AWK \
 472                         -v country="$country" \
 473                         -v region="$region" \
 474                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 475                 '
 476                         BEGIN {
 477                                 FS = "\t"
 478                                 cc = country
 479                                 while (getline <TZ_COUNTRY_TABLE) {
 480                                         if ($0 !~ /^#/  &&  country == $2) {
 481                                                 cc = $1
 482                                                 break
 483                                         }
 484                                 }
 485                         }
 486                         /^#/ { next }
 487                         $1 ~ cc && $4 == region { print $3 }
 488                 ' <"$TZ_ZONE_TABLE"`
 489                 esac
 490
 491                 # Make sure the corresponding zoneinfo file exists.
 492                 TZ_for_date=$TZDIR/$TZ
 493                 <"$TZ_for_date" || {
 494                         say >&2 "$0: time zone files are not set up correctly"
 495                         exit 1
 496                 }
 497         esac
 498
 499
 500         # Use the proposed TZ to output the current date relative to UTC.
 501         # Loop until they agree in seconds.
 502         # Give up after 8 unsuccessful tries.
 503
 504         extra_info=
 505         for i in 1 2 3 4 5 6 7 8
 506         do
 507                 TZdate=`LANG=C TZ="$TZ_for_date" date`
 508                 UTdate=`LANG=C TZ=UTC0 date`
 509                 TZsec=`expr "$TZdate" : '.*:\([0-5][0-9]\)'`
 510                 UTsec=`expr "$UTdate" : '.*:\([0-5][0-9]\)'`
 511                 case $TZsec in
 512                 $UTsec)
 513                         extra_info="
 514 Selected time is now:   $TZdate.
 515 Universal Time is now:  $UTdate."
 516                         break
 517                 esac
 518         done
 519
 520
 521         # Output TZ info and ask the user to confirm.
 522
 523         echo >&2 ""
 524         echo >&2 "The following information has been given:"
 525         echo >&2 ""
 526         case $country%$region%$coord in
 527         ?*%?*%) say >&2 "       $country$newline        $region";;
 528         ?*%%)   say >&2 "       $country";;
 529         %?*%?*) say >&2 "       coord $coord$newline    $region";;
 530         %%?*)   say >&2 "       coord $coord";;
 531         *)      say >&2 "       TZ='$TZ'"
 532         esac
 533         say >&2 ""
 534         say >&2 "Therefore TZ='$TZ' will be used.$extra_info"
 535         say >&2 "Is the above information OK?"
 536
 537         doselect Yes No
 538         ok=$select_result
 539         case $ok in
 540         Yes) break
 541         esac
 542 do coord=
 543 done
 544
 545 case $SHELL in
 546 *csh) file=.login line="setenv TZ '$TZ'";;
 547 *) file=.profile line="TZ='$TZ'; export TZ"
 548 esac
 549
 550 test -t 1 && say >&2 "
 551 You can make this change permanent for yourself by appending the line
 552         $line
 553 to the file '$file' in your home directory; then log out and log in again.
 554
 555 Here is that TZ value again, this time on standard output so that you
 556 can use the $0 command in shell scripts:"
 557
 558 say "$TZ"