Thanks a lot for your help and explanation. It's unfortunate that perl
doesn't generally come with this module by default, but python has a
function for this in the time module. Following your example, I came up
with one that should work on almost any system with python (python2 and
python3 compatible).
$ timestamp='2013年1月8日 20時19分'
$ time_format='%Y年%m月%d日 %H時%M分'
$ gdate -u -R -d "$(python -c 'import sys; from time import strptime;
t=strptime(sys.argv[-1],"'$time_format'"); print("%d-%d-%d
%d:%d"%(t.tm_year,t.tm_mon,t.tm_mday,t.tm_hour,t.tm_min))'
$timestamp)"
Tue, 08 Jan 2013 20:19:00 +0000
It might be nice if this was in the core of the date command, but it is
nice to know that you can offload onto other processes to accomplish this
if needed.
-Derek
On Fri, Jan 11, 2013 at 7:11 AM, Bob Proulx <[email protected]> wrote:
> Derek Ashley Thomas wrote:
> > I have a string with a custom date format written in Japanese: 2013年
> > 1月8日20時19分. I wish to convert this string to any other format
> > using date. I expected to use date -d "2013年1月8日 20時19分" +"%F
> > %R" but this produces the wrong date 2013-01-08 20:13 because it
> > sees the 2013 and converts it to hours-minutes (not year) and then
> > forgets the rest and assumes "today".
>
> There are multiple issues. At one level the locale specific date
> formats are not universially recognized. Date won't know what to do
> with the Japanese year, month, day symbols. Sorry.
>
> The next issue is that even without the localization issue that no
> time was specified. That is problematic. If no time is specified
> then 00:00 midnight is assumed. This often runs into daylight saving
> time problems. Better to avoid it and either use UTC or specify 12:00
> noon instead.
>
> > When I updated my machine to 'coreutils 8.20', the same command produces
> > the following error invalid date ‘2013年1月8日 20時19分’. While perhaps the
> > error is best since the date produced originally was wrong,
>
> Yes. That was the intention. Previously invalid dates did not
> produce correct results and resulted in other bugs.
>
> > is there any way using the date command to convert from a
> > custom/locale format to any other format?
>
> Unfortunately no. It is possible to convert from standardized date
> formats from one timezone to another timezone. And to produce
> localized output. But not to parse localized date formats.
>
> > In osx, the date command can be used to specifically convert
> > formats like so:
> >
> > timestamp="2013年1月8日 20時19分"
> > date -j -f "%Y年%m月%d日 %H時%M分" "$timestamp" +"%F %R"
>
> Sorry but no strptime(3) interface exists for GNU date. If someone
> were to put in the effort to produce such an interface I am sure the
> feature would be considered.
>
> At the moment the best I can suggest is to reduce the localization so
> that "2013年1月8日 20時19分" would be "2013-01-08 20:19 +0900" which
> can be parsed by GNU date.
>
> Alternatively I suggest using Perl (or Python or Ruby) to do this
> parsing. For example:
>
> $ perl -MPOSIX::strptime -le 'my ($sec, $min, $hour, $mday, $mon, $year,
> $wday, $yday) = POSIX::strptime("$ARGV[0]","%Y-%m-%d
> %H:%M");$year+=1900;$mon+=1;printf("%04d-%02d-%02d
> %0d:%02d\n",$year,$mon,$mday,$hour,$min);' "2013-01-08 20:19"
> 2013-01-08 20:19
>
> And therefore:
>
> $ perl -MPOSIX::strptime -le 'my ($sec, $min, $hour, $mday, $mon, $year,
> $wday, $yday) = POSIX::strptime("$ARGV[0]","%Y年%m月%d日
> %H時%M分");$year+=1900;$mon+=1;printf("%04d-%02d-%02d
> %0d:%02d\n",$year,$mon,$mday,$hour,$min);' "2013年1月8日 20時19分"
> 2013-01-08 20:19
>
> And therefore:
>
> $ date -u -R -d "$(perl -MPOSIX::strptime -le 'my ($sec, $min, $hour,
> $mday, $mon, $year, $wday, $yday) = POSIX::strptime("$ARGV[0]","%Y年%m月%d日
> %H時%M分");$year+=1900;$mon+=1;printf("%04d-%02d-%02d
> %0d:%02d\n",$year,$mon,$mday,$hour,$min);' "2013年1月8日 20時19分")"
> Tue, 08 Jan 2013 20:19:00 +0000
>
> You will probably not have POSIX::strptime installed by default and
> will need to install the module first.
>
> Bob
>
