What is the most efficient way to get a unix timestamp for a given ISO 8601 date and vice versa?
There are several third party websites to do this. However I am looking for a simple command that can be executed at the Linux prompt
Convert ISO Date/Time to Unix timestamp
date -d 'date' +"%s"
Example
bash-# date -d 'Fri Dec 8 00:12:50 UTC 2017' +"%s"
bash-# 1512691970
man -a date
-d, --date=STRING
display time described by STRING, not 'now'
%s seconds since 1970-01-01 00:00:00 UTC
Convert Unix timestamp to ISO Date/Time
date -Iseconds -d #<unix timestamp>
Example
bash-# date -Iseconds -d #1512711426
bash-# 2017-12-07T21:37:06-0800
man -a date
-d, --date=STRING
display time described by STRING, not 'now'
-I[TIMESPEC], --iso-8601[=TIMESPEC]
output date/time in ISO 8601 format.
TIMESPEC='date' for date only (the default), 'hours',
'minutes', 'seconds', or 'ns' for date and time to the
indicated precision.
Related
I'm trying to calculate the number of seconds since the Epoch, using date on MacOS BSD.
I can get a one year ago date string:
$ date -v -1y
Tue Apr 21 10:44:47 EST 2020
...but I can't figure out how to convert it into seconds since Epoch. Any suggestions?
Add +%s to tell it to print the datetime as seconds since the epoch:
date -v -1y +%s
The + is a date option to set the output format, and %s is strftime format for "seconds since epoch".
Portability note: while the +%s part is pretty standard and portable (though the %s format is not actually required by POSIX), the -v -1y part is wildly nonportable. With GNU date (e.g. on most Linuxes), you'd use something like --date='1 year ago' instead. On NetBSD, -d '1 year ago' works. Check your local man page to see what your system supports.
I want to convert specific/Input date to different timezone. I have tried below code.
dateYMD="2019/2/28 12:23:11.46"
timesydney=$(TZ=Australia/Sydney date -d "$dateYMD" +%s)
But above code give me a below error....
date: Not a recognized flag: d
Usage: date [-u] [+"Field Descriptors"]
What I intent to get is
$ xxx 2019-10-11 <= insert your command
1570752000
The output is timestamp in Oct 11 00:00:00 UTC 2019. I find a good way to do this in gnu, but not in bsd
This should work:
date -j -f '%F %T %Z' '2019-10-11 00:00:00 U' '+%s'
-j is for dry-run; i.e it prevents date from changing system date and time,
-f is for specifying input format,
+%s is for converting given date to seconds since Epoch.
On NetBSD the following will work:
TZ=GMT0 date -d '2019-10-11 00:00:00' '+%s'
Note the use of the TZ environment variable to specify the input timezone instead of trying to have it parsed from the input (though it may be possible to have a more properly formatted timezone parsed from the input, though then that leaves the question of what timezone the output should be formatted in).
On MacOS you might try something similar to what Oguz suggested:
TZ=GMT0 date -j -f '%Y-%m-%d %H:%M:%S' '2019-10-11 00:00:00' '+%s'
In mac osx bsd, date -vmon will convert the current date to Monday's date and date +%w displays day of week.
Say, I have input date 9/14/16 in the format mm/dd/yy. How can I convert this string pattern to a date object so that I could perform date functions like -vmon and +%w on it.
I tried the following: startDate=$(date -jf "%m/%d/%y" "9/14/16") and then tried to perform $startDate +"%w" but it doesn't work. I doubt that the startDate is not date and actually String.
How can I convert the string to date so that I perform date manipulation on it?
Edit: The requirement for doing this is: Say an input date is given. Then corresponding to that date, I want to get the beginning and ending working dates of the week i.e Monday's date and Friday's date. Then I want to get next week's Monday's date and Friday's date. How can I do this?
You need to use date twice, once to convert from the string input to an 'epoch time' (the number of seconds since The Epoch — aka 1970-01-01 00:00:00 +00:00), and once to convert an epoch time to an output format of your choosing:
rdate="9/14/16"
epoch_time=$(date -j -f '%m/%d/%y' "$rdate" +'%s')
date -j -vmon -r "$epoch_time"
date -j -vfri -r "$epoch_time" +'%w'
That gave me the output:
Mon Sep 12 10:14:44 PDT 2016
5
Note that Friday is day 5 of the week, so the output is correct. The use of %w when you specify -vdow seems a little moot; you know that the output will be 5. But you can use any other format characters that you need too.
Note that the time portion is defaulted to the current time. You could add 00:00:00 to the converted date and %H:%M:%S to the conversion format (-f argument) to work with midnight, etc.
You can combine it into one command line:
$ date -j -vmon -r $(date -j -f '%m/%d/%y %H:%M:%S' "$rdate 00:00:00" +'%s') +'%Y-%m-%d %H:%M:%S %w %s'
2016-09-12 00:00:00 1 1473663600
$
The last example on the man page for date on Mac OS X mentions the %s format specifier, which is the key to getting this to work. Well, that and using date twice.
Note that the man page gives synopses:
date [-ju] [-r seconds] [-v [+|-]val[ymwdHMS]] ... [+output_fmt]
date [-jnu] [[[mm]dd]HH]MM[[cc]yy][.ss]
date [-jnu] -f input_fmt new_date [+output_fmt]
date [-d dst] [-t minutes_west]
The 'usage' message is less helpful:
usage: date [-jnu] [-d dst] [-r seconds] [-t west] [-v[+|-]val[ymwdHMS]] ...
[-f fmt date | [[[mm]dd]HH]MM[[cc]yy][.ss]] [+format]
The usage message doesn't show that you can't use -f with -r or -v, whereas the manual is clear that you cannot.
Tested: Mac OS X 10.11.6 El Capitan
I have date format like 2016-02-26 14:12:36., I have to convert it into unix epoch time. I have the option to convert current time to epoch time using command : date +%s, however how to convert a specific date to epoch unix time
On the command line you convert the date provided to the UNIX epoch time like this:
date -j -f "%Y-%m-%d %H:%M:%S" "2016-02-26 14:12:36" "+%s"
This is on os x. The manual for date have some examples and strftime have all the formatting needed.
You can get seconds since the epoch from date like this ,
$ SECFROMEPOCH=`date --date="2016-02-26 14:12:36" +%s`
And then you can check the value that date gave back to you like this,
$ echo $SECFROMEPOCH | awk '{print strftime("%c",$1)}'