timezone/tzselect.ksh

   1 #! @KSH@
   2
   3 VERSION='@(#)tzselect.ksh       8.2'
   4
   5 # Ask the user about the time zone, and output the resulting TZ value to stdout.
   6 # Interact with the user via stderr and stdin.
   7
   8 # Contributed by Paul Eggert.
   9
  10 # Porting notes:
  11 #
  12 # This script requires several features of the Korn shell.
  13 # If your host lacks the Korn shell,
  14 # you can use either of the following free programs instead:
  15 #
  16 #       <a href=ftp://ftp.gnu.org/pub/gnu/>
  17 #       Bourne-Again shell (bash)
  18 #       </a>
  19 #
  20 #       <a href=ftp://ftp.cs.mun.ca/pub/pdksh/pdksh.tar.gz>
  21 #       Public domain ksh
  22 #       </a>
  23 #
  24 # This script also uses several features of modern awk programs.
  25 # If your host lacks awk, or has an old awk that does not conform to Posix.2,
  26 # you can use either of the following free programs instead:
  27 #
  28 #       <a href=ftp://ftp.gnu.org/pub/gnu/>
  29 #       GNU awk (gawk)
  30 #       </a>
  31 #
  32 #       <a href=ftp://ftp.whidbey.net/pub/brennan/>
  33 #       mawk
  34 #       </a>
  35
  36
  37 # Specify default values for environment variables if they are unset.
  38 : ${AWK=awk}
  39 : ${TZDIR=@TZDIR@}
  40
  41 # Check for awk Posix compliance.
  42 ($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
  43 [ $? = 123 ] || {
  44         echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
  45         exit 1
  46 }
  47
  48 if [ "$1" = "--help" ]; then
  49     cat <<EOF
  50 Usage: tzselect
  51 Select a time zone interactively.
  52
  53 Report bugs to tz@elsie.nci.nih.gov.
  54 EOF
  55     exit 0
  56 elif [ "$1" = "--version" ]; then
  57     cat <<EOF
  58 tzselect $VERSION
  59 EOF
  60     exit 0
  61 fi
  62
  63 # Make sure the tables are readable.
  64 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
  65 TZ_ZONE_TABLE=$TZDIR/zone.tab
  66 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
  67 do
  68         <$f || {
  69                 echo >&2 "$0: time zone files are not set up correctly"
  70                 exit 1
  71         }
  72 done
  73
  74 newline='
  75 '
  76 IFS=$newline
  77
  78
  79 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
  80 case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
  81 ?*) PS3=
  82 esac
  83
  84
  85 # Begin the main loop.  We come back here if the user wants to retry.
  86 while
  87
  88         echo >&2 'Please identify a location' \
  89                 'so that time zone rules can be set correctly.'
  90
  91         continent=
  92         country=
  93         region=
  94
  95
  96         # Ask the user for continent or ocean.
  97
  98         echo >&2 'Please select a continent or ocean.'
  99
 100         select continent in \
 101             Africa \
 102             Americas \
 103             Antarctica \
 104             'Arctic Ocean' \
 105             Asia \
 106             'Atlantic Ocean' \
 107             Australia \
 108             Europe \
 109             'Indian Ocean' \
 110             'Pacific Ocean' \
 111             'none - I want to specify the time zone using the Posix TZ format.'
 112         do
 113             case $continent in
 114             '')
 115                 echo >&2 'Please enter a number in range.';;
 116             ?*)
 117                 case $continent in
 118                 Americas) continent=America;;
 119                 *' '*) continent=$(expr "$continent" : '\([^ ]*\)')
 120                 esac
 121                 break
 122             esac
 123         done
 124         case $continent in
 125         '')
 126                 exit 1;;
 127         none)
 128                 # Ask the user for a Posix TZ string.  Check that it conforms.
 129                 while
 130                         echo >&2 'Please enter the desired value' \
 131                                 'of the TZ environment variable.'
 132                         echo >&2 'For example, GST-10 is a zone named GST' \
 133                                 'that is 10 hours ahead (east) of UTC.'
 134                         read TZ
 135                         $AWK -v TZ="$TZ" 'BEGIN {
 136                                 tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
 137                                 time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
 138                                 offset = "[-+]?" time
 139                                 date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
 140                                 datetime = "," date "(/" time ")?"
 141                                 tzpattern = "^(:.*|" tzname offset "(" tzname \
 142                                   "(" offset ")?(" datetime datetime ")?)?)$"
 143                                 if (TZ ~ tzpattern) exit 1
 144                                 exit 0
 145                         }'
 146                 do
 147                         echo >&2 "\`$TZ' is not a conforming" \
 148                                 'Posix time zone string.'
 149                 done
 150                 TZ_for_date=$TZ;;
 151         *)
 152                 # Get list of names of countries in the continent or ocean.
 153                 countries=$($AWK -F'\t' \
 154                         -v continent="$continent" \
 155                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 156                 '
 157                         /^#/ { next }
 158                         $3 ~ ("^" continent "/") {
 159                                 if (!cc_seen[$1]++) cc_list[++ccs] = $1
 160                         }
 161                         END {
 162                                 while (getline <TZ_COUNTRY_TABLE) {
 163                                         if ($0 !~ /^#/) cc_name[$1] = $2
 164                                 }
 165                                 for (i = 1; i <= ccs; i++) {
 166                                         country = cc_list[i]
 167                                         if (cc_name[country]) {
 168                                           country = cc_name[country]
 169                                         }
 170                                         print country
 171                                 }
 172                         }
 173                 ' <$TZ_ZONE_TABLE | sort -f)
 174
 175
 176                 # If there's more than one country, ask the user which one.
 177                 case $countries in
 178                 *"$newline"*)
 179                         echo >&2 'Please select a country.'
 180                         select country in $countries
 181                         do
 182                             case $country in
 183                             '') echo >&2 'Please enter a number in range.';;
 184                             ?*) break
 185                             esac
 186                         done
 187
 188                         case $country in
 189                         '') exit 1
 190                         esac;;
 191                 *)
 192                         country=$countries
 193                 esac
 194
 195
 196                 # Get list of names of time zone rule regions in the country.
 197                 regions=$($AWK -F'\t' \
 198                         -v country="$country" \
 199                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 200                 '
 201                         BEGIN {
 202                                 cc = country
 203                                 while (getline <TZ_COUNTRY_TABLE) {
 204                                         if ($0 !~ /^#/  &&  country == $2) {
 205                                                 cc = $1
 206                                                 break
 207                                         }
 208                                 }
 209                         }
 210                         $1 == cc { print $4 }
 211                 ' <$TZ_ZONE_TABLE)
 212
 213
 214                 # If there's more than one region, ask the user which one.
 215                 case $regions in
 216                 *"$newline"*)
 217                         echo >&2 'Please select one of the following' \
 218                                 'time zone regions.'
 219                         select region in $regions
 220                         do
 221                                 case $region in
 222                                 '') echo >&2 'Please enter a number in range.';;
 223                                 ?*) break
 224                                 esac
 225                         done
 226                         case $region in
 227                         '') exit 1
 228                         esac;;
 229                 *)
 230                         region=$regions
 231                 esac
 232
 233                 # Determine TZ from country and region.
 234                 TZ=$($AWK -F'\t' \
 235                         -v country="$country" \
 236                         -v region="$region" \
 237                         -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 238                 '
 239                         BEGIN {
 240                                 cc = country
 241                                 while (getline <TZ_COUNTRY_TABLE) {
 242                                         if ($0 !~ /^#/  &&  country == $2) {
 243                                                 cc = $1
 244                                                 break
 245                                         }
 246                                 }
 247                         }
 248                         $1 == cc && $4 == region { print $3 }
 249                 ' <$TZ_ZONE_TABLE)
 250
 251                 # Make sure the corresponding zoneinfo file exists.
 252                 TZ_for_date=$TZDIR/$TZ
 253                 <$TZ_for_date || {
 254                         echo >&2 "$0: time zone files are not set up correctly"
 255                         exit 1
 256                 }
 257         esac
 258
 259
 260         # Use the proposed TZ to output the current date relative to UTC.
 261         # Loop until they agree in seconds.
 262         # Give up after 8 unsuccessful tries.
 263
 264         extra_info=
 265         for i in 1 2 3 4 5 6 7 8
 266         do
 267                 TZdate=$(LANG=C TZ="$TZ_for_date" date)
 268                 UTdate=$(LANG=C TZ=UTC0 date)
 269                 TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
 270                 UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
 271                 case $TZsec in
 272                 $UTsec)
 273                         extra_info="
 274 Local time is now:      $TZdate.
 275 Universal Time is now:  $UTdate."
 276                         break
 277                 esac
 278         done
 279
 280
 281         # Output TZ info and ask the user to confirm.
 282
 283         echo >&2 ""
 284         echo >&2 "The following information has been given:"
 285         echo >&2 ""
 286         case $country+$region in
 287         ?*+?*)  echo >&2 "      $country$newline        $region";;
 288         ?*+)    echo >&2 "      $country";;
 289         +)      echo >&2 "      TZ='$TZ'"
 290         esac
 291         echo >&2 ""
 292         echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
 293         echo >&2 "Is the above information OK?"
 294
 295         ok=
 296         select ok in Yes No
 297         do
 298             case $ok in
 299             '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
 300             ?*) break
 301             esac
 302         done
 303         case $ok in
 304         '') exit 1;;
 305         Yes) break
 306         esac
 307 do :
 308 done
 309
 310 case $SHELL in
 311 *csh) file=.login line="setenv TZ '$TZ'";;
 312 *) file=.profile line="TZ='$TZ'; export TZ"
 313 esac
 314
 315 echo >&2 "
 316 You can make this change permanent for yourself by appending the line
 317         $line
 318 to the file '$file' in your home directory; then log out and log in again.
 319
 320 Here is that TZ value again, this time on standard output so that you
 321 can use the $0 command in shell scripts:"
 322
 323 echo "$TZ"