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tzselect.ksh revision 1.5 
      1 #! /bin/ksh
      2 #
      3 #	$NetBSD: tzselect.ksh,v 1.5 1999/11/10 20:32:31 kleink Exp $
      4 #
      5 # '@(#)tzselect.ksh	1.7'
      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 <eggert (at] twinsun.com>.
     11 
     12 # Porting notes:
     13 #
     14 # This script requires several features of the Korn shell.
     15 # If your host lacks the Korn shell,
     16 # you can use either of the following free programs instead:
     17 #
     18 #	<a href=ftp://ftp.gnu.org/pub/gnu/>
     19 #	Bourne-Again shell (bash)
     20 #	</a>
     21 #
     22 #	<a href=ftp://ftp.cs.mun.ca/pub/pdksh/pdksh.tar.gz>
     23 #	Public domain ksh
     24 #	</a>
     25 #
     26 # This script also uses several features of modern awk programs.
     27 # If your host lacks awk, or has an old awk that does not conform to Posix.2,
     28 # you can use either of the following free programs instead:
     29 #
     30 #	<a href=ftp://ftp.gnu.org/pub/gnu/>
     31 #	GNU awk (gawk)
     32 #	</a>
     33 #
     34 #	<a href=ftp://ftp.whidbey.net/pub/brennan/>
     35 #	mawk
     36 #	</a>
     37 
     38 
     39 # Specify default values for environment variables if they are unset.
     40 : ${AWK=awk}
     41 : ${TZDIR=$(pwd)}
     42 
     43 # Check for awk Posix compliance.
     44 ($AWK -v x=y 'BEGIN { exit 123 }') </dev/null >/dev/null 2>&1
     45 [ $? = 123 ] || {
     46 	echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
     47 	exit 1
     48 }
     49 
     50 # Make sure the tables are readable.
     51 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
     52 TZ_ZONE_TABLE=$TZDIR/zone.tab
     53 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
     54 do
     55 	<$f || {
     56 		echo >&2 "$0: time zone files are not set up correctly"
     57 		exit 1
     58 	}
     59 done
     60 
     61 newline='
     62 '
     63 IFS=$newline
     64 
     65 
     66 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
     67 case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
     68 ?*) PS3=
     69 esac
     70 
     71 
     72 # Begin the main loop.  We come back here if the user wants to retry.
     73 while
     74 
     75 	echo >&2 'Please identify a location' \
     76 		'so that time zone rules can be set correctly.'
     77 
     78 	continent=
     79 	country=
     80 	region=
     81 
     82 
     83 	# Ask the user for continent or ocean.
     84 
     85 	echo >&2 'Please select a continent or ocean.'
     86 
     87 	select continent in \
     88 	    Africa \
     89 	    Americas \
     90 	    Antarctica \
     91 	    'Arctic Ocean' \
     92 	    Asia \
     93 	    'Atlantic Ocean' \
     94 	    Australia \
     95 	    Europe \
     96 	    'Indian Ocean' \
     97 	    'Pacific Ocean' \
     98 	    'none - I want to specify the time zone using the Posix TZ format.'
     99 	do
    100 	    case $continent in
    101 	    '')
    102 		echo >&2 'Please enter a number in range.';;
    103 	    ?*)
    104 		case $continent in
    105 		Americas) continent=America;;
    106 		*' '*) continent=$(expr "$continent" : '\([^ ]*\)')
    107 		esac
    108 		break
    109 	    esac
    110 	done
    111 	case $continent in
    112 	'')
    113 		exit 1;;
    114 	none)
    115 		# Ask the user for a Posix TZ string.  Check that it conforms.
    116 		while
    117 			echo >&2 'Please enter the desired value' \
    118 				'of the TZ environment variable.'
    119 			echo >&2 'For example, GST-10 is a zone named GST' \
    120 				'that is 10 hours ahead (east) of UTC.'
    121 			read TZ
    122 			$AWK -v TZ="$TZ" 'BEGIN {
    123 				tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
    124 				time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
    125 				offset = "[-+]?" time
    126 				date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
    127 				datetime = "," date "(/" time ")?"
    128 				tzpattern = "^(:.*|" tzname offset "(" tzname \
    129 				  "(" offset ")?(" datetime datetime ")?)?)$"
    130 				if (TZ ~ tzpattern) exit 1
    131 				exit 0
    132 			}'
    133 		do
    134 			echo >&2 "\`$TZ' is not a conforming" \
    135 				'Posix time zone string.'
    136 		done
    137 		TZ_for_date=$TZ;;
    138 	*)
    139 		# Get list of names of countries in the continent or ocean.
    140 		countries=$($AWK -F'\t' \
    141 			-v continent="$continent" \
    142 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
    143 		'
    144 			/^#/ { next }
    145 			$3 ~ ("^" continent "/") {
    146 				if (!cc_seen[$1]++) cc_list[++ccs] = $1
    147 			}
    148 			END {
    149 				while (getline <TZ_COUNTRY_TABLE) {
    150 					if ($0 !~ /^#/) cc_name[$1] = $2
    151 				}
    152 				for (i = 1; i <= ccs; i++) {
    153 					country = cc_list[i]
    154 					if (cc_name[country]) {
    155 					  country = cc_name[country]
    156 					}
    157 					print country
    158 				}
    159 			}
    160 		' <$TZ_ZONE_TABLE | sort -f)
    161 
    162 
    163 		# If there's more than one country, ask the user which one.
    164 		case $countries in
    165 		*"$newline"*)
    166 			echo >&2 'Please select a country.'
    167 			select country in $countries
    168 			do
    169 			    case $country in
    170 			    '') echo >&2 'Please enter a number in range.';;
    171 			    ?*) break
    172 			    esac
    173 			done
    174 
    175 			case $country in
    176 			'') exit 1
    177 			esac;;
    178 		*)
    179 			country=$countries
    180 		esac
    181 
    182 
    183 		# Get list of names of time zone rule regions in the country.
    184 		regions=$($AWK -F'\t' \
    185 			-v country="$country" \
    186 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
    187 		'
    188 			BEGIN {
    189 				cc = country
    190 				while (getline <TZ_COUNTRY_TABLE) {
    191 					if ($0 !~ /^#/  &&  country == $2) {
    192 						cc = $1
    193 						break
    194 					}
    195 				}
    196 			}
    197 			$1 == cc { print $4 }
    198 		' <$TZ_ZONE_TABLE)
    199 
    200 
    201 		# If there's more than one region, ask the user which one.
    202 		case $regions in
    203 		*"$newline"*)
    204 			echo >&2 'Please select one of the following' \
    205 				'time zone regions.'
    206 			select region in $regions
    207 			do
    208 				case $region in
    209 				'') echo >&2 'Please enter a number in range.';;
    210 				?*) break
    211 				esac
    212 			done
    213 			case $region in
    214 			'') exit 1
    215 			esac;;
    216 		*)
    217 			region=$regions
    218 		esac
    219 
    220 		# Determine TZ from country and region.
    221 		TZ=$($AWK -F'\t' \
    222 			-v country="$country" \
    223 			-v region="$region" \
    224 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
    225 		'
    226 			BEGIN {
    227 				cc = country
    228 				while (getline <TZ_COUNTRY_TABLE) {
    229 					if ($0 !~ /^#/  &&  country == $2) {
    230 						cc = $1
    231 						break
    232 					}
    233 				}
    234 			}
    235 			$1 == cc && $4 == region { print $3 }
    236 		' <$TZ_ZONE_TABLE)
    237 
    238 		# Make sure the corresponding zoneinfo file exists.
    239 		TZ_for_date=$TZDIR/$TZ
    240 		<$TZ_for_date || {
    241 			echo >&2 "$0: time zone files are not set up correctly"
    242 			exit 1
    243 		}
    244 	esac
    245 
    246 
    247 	# Use the proposed TZ to output the current date relative to UTC.
    248 	# Loop until they agree in seconds.
    249 	# Give up after 8 unsuccessful tries.
    250 
    251 	extra_info=
    252 	for i in 1 2 3 4 5 6 7 8
    253 	do
    254 		TZdate=$(LANG=C TZ="$TZ_for_date" date)
    255 		UTdate=$(LANG=C TZ=UTC0 date)
    256 		TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
    257 		UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
    258 		case $TZsec in
    259 		$UTsec)
    260 			extra_info="
    261 Local time is now:	$TZdate.
    262 Universal Time is now:	$UTdate."
    263 			break
    264 		esac
    265 	done
    266 
    267 
    268 	# Output TZ info and ask the user to confirm.
    269 
    270 	echo >&2 ""
    271 	echo >&2 "The following information has been given:"
    272 	echo >&2 ""
    273 	case $country+$region in
    274 	?*+?*)	echo >&2 "	$country$newline	$region";;
    275 	?*+)	echo >&2 "	$country";;
    276 	+)	echo >&2 "	TZ='$TZ'"
    277 	esac
    278 	echo >&2 ""
    279 	echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
    280 	echo >&2 "Is the above information OK?"
    281 
    282 	ok=
    283 	select ok in Yes No
    284 	do
    285 	    case $ok in
    286 	    '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
    287 	    ?*) break
    288 	    esac
    289 	done
    290 	case $ok in
    291 	'') exit 1;;
    292 	Yes) break
    293 	esac
    294 do :
    295 done
    296 
    297 case $SHELL in
    298 *csh) file=.login line="setenv TZ '$TZ'";;
    299 *) file=.profile line="TZ='$TZ'; export TZ"
    300 esac
    301 
    302 echo >&2 "
    303 You can make this change permanent for yourself by appending the line
    304 	$line
    305 to the file '$file' in your home directory; then log out and log in again.
    306 
    307 Here is that TZ value again, this time on standard output so that you
    308 can use the $0 command in shell scripts:"
    309 
    310 echo "$TZ"
    311