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