3 # '@(#)tzselect.ksh 1.7'
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.
8 # Contributed by Paul Eggert <eggert@twinsun.com>.
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:
16 # <a href=ftp://ftp.gnu.org/pub/gnu/>
17 # Bourne-Again shell (bash)
20 # <a href=ftp://ftp.cs.mun.ca/pub/pdksh/pdksh.tar.gz>
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:
28 # <a href=ftp://ftp.gnu.org/pub/gnu/>
32 # <a href=ftp://ftp.whidbey.net/pub/brennan/>
37 # Specify default values for environment variables if they are unset.
41 # Check for awk Posix compliance.
42 ($AWK -v x
=y
'BEGIN { exit 123 }') </dev
/null
>/dev
/null
2>&1
44 echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
48 # Make sure the tables are readable.
49 TZ_COUNTRY_TABLE
=$TZDIR/iso3166.tab
50 TZ_ZONE_TABLE
=$TZDIR/zone.tab
51 for f
in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
54 echo >&2 "$0: time zone files are not set up correctly"
64 # Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
65 case $
(echo 1 |
(select x
in x
; do break; done) 2>/dev
/null
) in
70 # Begin the main loop. We come back here if the user wants to retry.
73 echo >&2 'Please identify a location' \
74 'so that time zone rules can be set correctly.'
81 # Ask the user for continent or ocean.
83 echo >&2 'Please select a continent or ocean.'
96 'none - I want to specify the time zone using the Posix TZ format.'
100 echo >&2 'Please enter a number in range.';;
103 Americas
) continent
=America
;;
104 *' '*) continent
=$
(expr "$continent" : '\([^ ]*\)')
113 # Ask the user for a Posix TZ string. Check that it conforms.
115 echo >&2 'Please enter the desired value' \
116 'of the TZ environment variable.'
117 echo >&2 'For example, GST-10 is a zone named GST' \
118 'that is 10 hours ahead (east) of UTC.'
120 $AWK -v TZ
="$TZ" 'BEGIN {
121 tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
122 time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
123 offset = "[-+]?" time
124 date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
125 datetime = "," date "(/" time ")?"
126 tzpattern = "^(:.*|" tzname offset "(" tzname \
127 "(" offset ")?(" datetime datetime ")?)?)$"
128 if (TZ ~ tzpattern) exit 1
132 echo >&2 "\`$TZ' is not a conforming" \
133 'Posix time zone string.'
137 # Get list of names of countries in the continent or ocean.
138 countries
=$
($AWK -F'\t' \
139 -v continent
="$continent" \
140 -v TZ_COUNTRY_TABLE
="$TZ_COUNTRY_TABLE" \
143 $3 ~ ("^" continent "/") {
144 if (!cc_seen[$1]++) cc_list[++ccs] = $1
147 while (getline <TZ_COUNTRY_TABLE) {
148 if ($0 !~ /^#/) cc_name[$1] = $2
150 for (i = 1; i <= ccs; i++) {
152 if (cc_name[country]) {
153 country = cc_name[country]
158 ' <$TZ_ZONE_TABLE |
sort -f)
161 # If there's more than one country, ask the user which one.
164 echo >&2 'Please select a country.'
165 select country
in $countries
168 '') echo >&2 'Please enter a number in range.';;
181 # Get list of names of time zone rule regions in the country.
182 regions
=$
($AWK -F'\t' \
183 -v country
="$country" \
184 -v TZ_COUNTRY_TABLE
="$TZ_COUNTRY_TABLE" \
188 while (getline <TZ_COUNTRY_TABLE) {
189 if ($0 !~ /^#/ && country == $2) {
195 $1 == cc { print $4 }
199 # If there's more than one region, ask the user which one.
202 echo >&2 'Please select one of the following' \
204 select region
in $regions
207 '') echo >&2 'Please enter a number in range.';;
218 # Determine TZ from country and region.
220 -v country
="$country" \
221 -v region
="$region" \
222 -v TZ_COUNTRY_TABLE
="$TZ_COUNTRY_TABLE" \
226 while (getline <TZ_COUNTRY_TABLE) {
227 if ($0 !~ /^#/ && country == $2) {
233 $1 == cc && $4 == region { print $3 }
236 # Make sure the corresponding zoneinfo file exists.
237 TZ_for_date
=$TZDIR/$TZ
239 echo >&2 "$0: time zone files are not set up correctly"
245 # Use the proposed TZ to output the current date relative to UTC.
246 # Loop until they agree in seconds.
247 # Give up after 8 unsuccessful tries.
250 for i
in 1 2 3 4 5 6 7 8
252 TZdate
=$
(LANG
=C TZ
="$TZ_for_date" date)
253 UTdate
=$
(LANG
=C TZ
=UTC0
date)
254 TZsec
=$
(expr "$TZdate" : '.*:\([0-5][0-9]\)')
255 UTsec
=$
(expr "$UTdate" : '.*:\([0-5][0-9]\)')
259 Local time is now: $TZdate.
260 Universal Time is now: $UTdate."
266 # Output TZ info and ask the user to confirm.
269 echo >&2 "The following information has been given:"
271 case $country+$region in
272 ?
*+?
*) echo >&2 " $country$newline $region";;
273 ?
*+) echo >&2 " $country";;
274 +) echo >&2 " TZ='$TZ'"
277 echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
278 echo >&2 "Is the above information OK?"
284 '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
296 *csh
) file=.login line
="setenv TZ '$TZ'";;
297 *) file=.profile line
="TZ='$TZ'; export TZ"
301 You can make this change permanent for yourself by appending the line
303 to the file '$file' in your home directory; then log out and log in again.
305 Here is that TZ value again, this time on standard output so that you
306 can use the $0 command in shell scripts:"