What is epoch time?

The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds (in ISO 8601: 1970-01-01T00:00:00Z). Literally speaking the epoch is Unix time 0 (midnight 1/1/1970), but ‘epoch’ is often used as a synonym for ‘Unix time’. Many Unix systems store epoch dates as a signed 32-bit integer, which might cause problems on January 19, 2038 (known as the Year 2038 problem or Y2038).

How to get the current epoch time in …

Convert from human readable date to epoch

Perl	Use the Perl Epoch routines
PHP	mktime(hour, minute, second, month, day, year)
Ruby	Time.local(year, month, day, hour, minute, second, usec ) (or Time.gm for GMT/UTC input). To display add .to_i
Python	import time first, then int(time.mktime(time.strptime(‘2000-01-01 12:34:00’, ‘%Y-%m-%d %H:%M:%S’))) – time.timezone
Java	long epoch = new java.text.SimpleDateFormat (“MM/dd/yyyy HH:mm:ss”).parse(“01/01/1970 01:00:00”).getTime();
VBScript/ASP	DateDiff(“s”, “01/01/1970 00:00:00”, time field)
C	Use the C Epoch Converter routines
R	as.numeric(as.POSIXct(“MM/dd/yyyy HH:mm:ss”, origin=”1970-01-01″))
MySQL	SELECT unix_timestamp(time) Time format: YYYY-MM-DD HH:MM:SS or YYMMDD or YYYYMMDD More on using Epoch timestamps with MySQL
PostgreSQL	SELECT extract(epoch FROM date(‘2000-01-01 12:34’)); With timestamp: SELECT EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE ‘2001-02-16 20:38:40-08’); With interval: SELECT EXTRACT(EPOCH FROM INTERVAL ‘5 days 3 hours’);
SQL Server	SELECT DATEDIFF(s, ‘1970-01-01 00:00:00’, time field)
JavaScript	Use the JavaScript Date object
Unix/Linux Shell	date +%s -d”Jan 1, 1980 00:00:01″ Replace ‘-d’ with ‘-ud’ to input in GMT/UTC time.

Convert from epoch to human readable date

Perl	Use the Perl Epoch routines
PHP	date(output format, epoch); Output format example: ‘r’ = RFC 2822 date
Ruby	Time.at(epoch)
Python	import time first, then time.strftime(“%a, %d %b %Y %H:%M:%S +0000”, time.localtime(epoch)) Replace time.localtime with time.gmtime for GMT time.
Java	String date = new java.text.SimpleDateFormat(“MM/dd/yyyy HH:mm:ss”).format(new java.util.Date (epoch*1000));
VBScript/ASP	DateAdd(“s”, epoch, “01/01/1970 00:00:00”)
C	Use the C Epoch Converter routines
R	as.POSIXct(epoch, origin=”1970-01-01″)
MySQL	from_unixtime(epoch, optional output format) The default output format is YYY-MM-DD HH:MM:SS more …
PostgreSQL	PostgreSQL version 8.1 and higher: SELECT to_timestamp(epoch); Older versions: SELECT TIMESTAMP WITH TIME ZONE ‘epoch’ + epoch * INTERVAL ‘1 second’;
Oracle PL/SQL	SELECT to_date(’01-JAN-1970′,’dd-mon-yyyy’)+(1326357743/60/60/24) from dual Replace 1326357743 with epoch.
SQL Server	DATEADD(s, epoch, ‘1970-01-01 00:00:00’)
Microsoft Excel	=(A1 / 86400) + 25569 Format the result cell for date/time, the result will be in GMT time (A1 is the cell with the epoch number). For other time zones: =((A1 +/- time zone adjustment) / 86400) + 25569.
Crystal Reports	DateAdd(“s”, {EpochTimeStampField}-14400, #1/1/1970 00:00:00#) -14400 used for Eastern Standard Time. See Time Zones.
JavaScript	Use the JavaScript Date object
Tcl/Tk	clock format 1325376000
Unix/Linux Shell	date -d @1190000000 Replace 1190000000 with your epoch, needs recent version of ‘date’. Replace ‘-d’ with ‘-ud’ for GMT/UTC time.
PowerShell	Function get-epochDate ($epochDate) { [timezone]::CurrentTimeZone.ToLocalTime(([datetime]’1/1/1970′).AddSeconds($epochDate)) }, then use: get-epochDate 1279152364. Works for Windows PowerShell v1 and v2
Other OS’s	Command line: perl -e “print scalar(localtime(epoch))” (If Perl is installed) Replace ‘localtime’ with ‘gmtime’ for GMT/UTC time.

Reference

http://www.epochconverter.com/

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