Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
On Fri, Aug 12, 2022 at 12:18:20PM +0200, Uwe Kleine-König wrote: uwe@taurus:/usr/share/zoneinfo$ TZ=Europe/London date Fri Aug 12 11:13:34 AM BST 2022 uwe@taurus:/usr/share/zoneinfo$ TZ=BST date Fri Aug 12 10:13:38 AM BST 2022 The first one is the right one, but there is no way to determine the latter to be wrong. Apart from the offset the output is identical and if you're not aware that TZ=BST is wrong you have no chance to notice that. If it at least said "Fri Aug 12 11:13:38 AM UTC 2022" or (better yet) dies with an error code that would be highly convenient. It would also be non-compliant with the standard. I'll pile on with what everyone else said, and repeat that the only practical solution is to not do what you're doing because the functionality is fundamentally unreliable. The ideal solution would be to drop support for three letter timezone codes entirely, but that's untenable from a compatibility standpoint.
Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
On 12/08/2022 11:18, Uwe Kleine-König wrote: On Sun, May 05, 2013 at 05:43:38PM -0600, Bob Proulx wrote: severity 705566 normal thanks Laurence Maddox wrote: I get this output: Current default time zone: 'America/Chicago' Local time is now: Tue Apr 16 14:45:29 CDT 2013. Universal Time is now: Tue Apr 16 19:45:29 UTC 2013. Looks okay. What output did you expect? I need to view on the CLI the time in various timezones. ... I have searched for the "right" way to complete my task, and found a link here: http://www.linuxquestions.org/questions/programming-9/display-different-timezones-in-command-line-927660/ That link recommends that I complete my task using a command like this one: TZ=UTC date && TZ=CDT date && TZ=IST date The concept is reasonable but you must pick a correct timezone for what you want to accomplish. UTC is okay. But CDT and IST are meaningless to libc. The GNU libc has no concept of invalid timezones. If a timezone doesn't match anything else then the default is that it is a name for UTC. So basically you have asked for UTC three times in a row. I stumbled about a similar thing just now and would consider this behaviour at least inconsistent: uwe@taurus:/usr/share/zoneinfo$ TZ=Europe/London date Fri Aug 12 11:13:34 AM BST 2022 uwe@taurus:/usr/share/zoneinfo$ TZ=BST date Fri Aug 12 10:13:38 AM BST 2022 The first one is the right one, but there is no way to determine the latter to be wrong. Apart from the offset the output is identical and if you're not aware that TZ=BST is wrong you have no chance to notice that. If it at least said "Fri Aug 12 11:13:38 AM UTC 2022" or (better yet) dies with an error code that would be highly convenient. And given that the timezone specifier in the output is "BST" (in both cases!) noticing that TZ=BST is wrong isn't as trivial as it should be. Note that using -R doesn't help here either because then I have to notice that "+" is wrong, but to find the offset from me to BST was the actual task to solve here ... In my experience using POSIX timezone specifications leads to ambiguity and they're not really usable. Instead it's best to use the longer form location based zones where possible. I've expanded on this here: https://www.pixelbeat.org/docs/linux_timezones/ thanks, Pádraig
Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
On Sun, May 05, 2013 at 05:43:38PM -0600, Bob Proulx wrote: > severity 705566 normal > thanks > > Laurence Maddox wrote: > > I get this output: > > Current default time zone: 'America/Chicago' > > Local time is now: Tue Apr 16 14:45:29 CDT 2013. > > Universal Time is now: Tue Apr 16 19:45:29 UTC 2013. > > Looks okay. What output did you expect? > > > I need to view on the CLI the time in various timezones. > > ... > > I have searched for the "right" way to complete my task, and found a link > > here: > > http://www.linuxquestions.org/questions/programming-9/display-different-timezones-in-command-line-927660/ > > > > That link recommends that I complete my task using a command like this one: > > TZ=UTC date && TZ=CDT date && TZ=IST date > > The concept is reasonable but you must pick a correct timezone for > what you want to accomplish. UTC is okay. But CDT and IST are > meaningless to libc. The GNU libc has no concept of invalid > timezones. If a timezone doesn't match anything else then the default > is that it is a name for UTC. So basically you have asked for UTC > three times in a row. I stumbled about a similar thing just now and would consider this behaviour at least inconsistent: uwe@taurus:/usr/share/zoneinfo$ TZ=Europe/London date Fri Aug 12 11:13:34 AM BST 2022 uwe@taurus:/usr/share/zoneinfo$ TZ=BST date Fri Aug 12 10:13:38 AM BST 2022 The first one is the right one, but there is no way to determine the latter to be wrong. Apart from the offset the output is identical and if you're not aware that TZ=BST is wrong you have no chance to notice that. If it at least said "Fri Aug 12 11:13:38 AM UTC 2022" or (better yet) dies with an error code that would be highly convenient. And given that the timezone specifier in the output is "BST" (in both cases!) noticing that TZ=BST is wrong isn't as trivial as it should be. Note that using -R doesn't help here either because then I have to notice that "+" is wrong, but to find the offset from me to BST was the actual task to solve here ... Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König| Industrial Linux Solutions | https://www.pengutronix.de/ | signature.asc Description: PGP signature
Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
severity 705566 normal thanks Laurence Maddox wrote: I get this output: Current default time zone: 'America/Chicago' Local time is now: Tue Apr 16 14:45:29 CDT 2013. Universal Time is now: Tue Apr 16 19:45:29 UTC 2013. Looks okay. What output did you expect? I need to view on the CLI the time in various timezones. ... I have searched for the right way to complete my task, and found a link here: http://www.linuxquestions.org/questions/programming-9/display-different-timezones-in-command-line-927660/ That link recommends that I complete my task using a command like this one: TZ=UTC date TZ=CDT date TZ=IST date The concept is reasonable but you must pick a correct timezone for what you want to accomplish. UTC is okay. But CDT and IST are meaningless to libc. The GNU libc has no concept of invalid timezones. If a timezone doesn't match anything else then the default is that it is a name for UTC. So basically you have asked for UTC three times in a row. However, I get this output, which is obviously not what it should be: Tue Apr 16 19:45:39 UTC 2013 Tue Apr 16 19:45:39 CDT 2013 Tue Apr 16 19:45:39 IST 2013 Try this: $ env TZ=US/Eastern date Sun May 5 19:37:04 EDT 2013 $ env TZ=US/Central date Sun May 5 18:37:07 CDT 2013 $ env TZ=US/Mountain date Sun May 5 17:37:07 MDT 2013 $ env TZ=US/Pacific date Sun May 5 16:37:08 PDT 2013 However the named timezones are ambiguous. The use of the above legacy format is really terrible for knowing for sure what time it is and which timezone you are in. That is the entire reason for the standard time strings. I use and recommend -R to print the time string in an unambiguous standard format. $ env TZ=US/Mountain date -R Sun, 05 May 2013 17:43:03 -0600 See also the FAQ where there is extensive discussion of using the date command for this task. http://www.gnu.org/software/coreutils/faq/#The-date-command-is-not-working-right_002e Bob signature.asc Description: Digital signature
Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
reassign 705566 quit 'date' is /bin/date, from package coreutils. This bug was filed against (source) package date for R package r-bin-date, which is not providing /bin/date. Dirk On 16 April 2013 at 13:09, Laurence Maddox wrote: | Package: date | Severity: important | Tags: l10n | | I need to view on the CLI the time in various timezones. | | | | I have correctly configured the time and timezone to the best of my knowledge. | I use this command: | dpkg-reconfigure tzdata ntpdate pool.ntp.org hwclock --systohc --utc | | | | I get this output: | Current default time zone: 'America/Chicago' | Local time is now: Tue Apr 16 14:45:29 CDT 2013. | Universal Time is now: Tue Apr 16 19:45:29 UTC 2013. | | 16 Apr 19:45:38 ntpdate[12036]: adjust time server 199.102.46.73 offset | -0.036668 sec | | | | | I have searched for the right way to complete my task, and found a link here: | http://www.linuxquestions.org/questions/programming-9/ | display-different-timezones-in-command-line-927660/ | | That link recommends that I complete my task using a command like this one: | TZ=UTC date TZ=CDT date TZ=IST date | | | | However, I get this output, which is obviously not what it should be: | Tue Apr 16 19:45:39 UTC 2013 | Tue Apr 16 19:45:39 CDT 2013 | Tue Apr 16 19:45:39 IST 2013 | | | -- System Information: | Debian Release: 6.0.6 | APT prefers stable-updates | APT policy: (500, 'stable-updates'), (500, 'proposed-updates'), (500, | 'testing'), (500, 'stable') | Architecture: amd64 (x86_64) | | Kernel: Linux 2.6.32-5-amd64 (SMP w/8 CPU cores) | Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) | Shell: /bin/sh linked to /bin/dash -- Dirk Eddelbuettel | e...@debian.org | http://dirk.eddelbuettel.com -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
Package: date Severity: important Tags: l10n I need to view on the CLI the time in various timezones. I have correctly configured the time and timezone to the best of my knowledge. I use this command: dpkg-reconfigure tzdata ntpdate pool.ntp.org hwclock --systohc --utc I get this output: Current default time zone: 'America/Chicago' Local time is now: Tue Apr 16 14:45:29 CDT 2013. Universal Time is now: Tue Apr 16 19:45:29 UTC 2013. 16 Apr 19:45:38 ntpdate[12036]: adjust time server 199.102.46.73 offset -0.036668 sec I have searched for the right way to complete my task, and found a link here: http://www.linuxquestions.org/questions/programming-9/display-different-timezones-in-command-line-927660/ That link recommends that I complete my task using a command like this one: TZ=UTC date TZ=CDT date TZ=IST date However, I get this output, which is obviously not what it should be: Tue Apr 16 19:45:39 UTC 2013 Tue Apr 16 19:45:39 CDT 2013 Tue Apr 16 19:45:39 IST 2013 -- System Information: Debian Release: 6.0.6 APT prefers stable-updates APT policy: (500, 'stable-updates'), (500, 'proposed-updates'), (500, 'testing'), (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 2.6.32-5-amd64 (SMP w/8 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash
Bug#705566: date does not read the timezone from the environment variable TZ, and there is no other way to view from the CLI times in other timezones.
On 16 April 2013 at 13:09, Laurence Maddox wrote: | Package: date | Severity: important | Tags: l10n | | I need to view on the CLI the time in various timezones. | | | | I have correctly configured the time and timezone to the best of my knowledge. | I use this command: | dpkg-reconfigure tzdata ntpdate pool.ntp.org hwclock --systohc --utc | Here is a simple counter-example: edd@max:~$ date # my local time Tue Apr 16 15:49:02 CDT 2013 edd@max:~$ TZ=America/Los_Angeles date # arbitrary other TZ Tue Apr 16 13:49:15 PDT 2013 which works just fine. edd@max:~$ which date /bin/date edd@max:~$ date --version date (GNU coreutils) 8.13 Copyright (C) 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later http://gnu.org/licenses/gpl.html. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Written by David MacKenzie. edd@max:~$ Dirk | | | I get this output: | Current default time zone: 'America/Chicago' | Local time is now: Tue Apr 16 14:45:29 CDT 2013. | Universal Time is now: Tue Apr 16 19:45:29 UTC 2013. | | 16 Apr 19:45:38 ntpdate[12036]: adjust time server 199.102.46.73 offset | -0.036668 sec | | | | | I have searched for the right way to complete my task, and found a link here: | http://www.linuxquestions.org/questions/programming-9/ | display-different-timezones-in-command-line-927660/ | | That link recommends that I complete my task using a command like this one: | TZ=UTC date TZ=CDT date TZ=IST date | | | | However, I get this output, which is obviously not what it should be: | Tue Apr 16 19:45:39 UTC 2013 | Tue Apr 16 19:45:39 CDT 2013 | Tue Apr 16 19:45:39 IST 2013 | | | -- System Information: | Debian Release: 6.0.6 | APT prefers stable-updates | APT policy: (500, 'stable-updates'), (500, 'proposed-updates'), (500, | 'testing'), (500, 'stable') | Architecture: amd64 (x86_64) | | Kernel: Linux 2.6.32-5-amd64 (SMP w/8 CPU cores) | Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) | Shell: /bin/sh linked to /bin/dash -- Dirk Eddelbuettel | e...@debian.org | http://dirk.eddelbuettel.com -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org
