timezone/tzselect.ksh

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