Perl	time
PHP	time()
Ruby	Time.now (or Time.new). To display the epoch: Time.now.to_i
Python	import time first, then time.time()
Java	long epoch = System.currentTimeMillis()/1000;
Microsoft .NET C#	epoch = (DateTime.Now.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
VBScript/ASP	DateDiff("s", "01/01/1970 00:00:00", Now())
Erlang	calendar:datetime_to_gregorian_seconds(calendar:now_to_universal_time( now()))-719528*24*3600.
MySQL	SELECT unix_timestamp(now())
PostgreSQL	SELECT extract(epoch FROM now());
Oracle PL/SQL	SELECT (SYSDATE - TO_DATE('01-01-1970 00:00:00', 'DD-MM-YYYY HH24:MI:SS')) * 24 * 60 * 60 FROM DUAL
SQL Server	SELECT DATEDIFF(s, '1970-01-01 00:00:00', GETUTCDATE())
JavaScript	Math.round(new Date().getTime()/1000.0) getTime() returns time in milliseconds.
Unix/Linux	date +%s
PowerShell	Get-Date -UFormat "%s" Produces: 1279152364.63599
Other OS’s	Command line: perl -e "print time" (If Perl is installed on your system)

Convert from human readable date to epoch

Perl	Use these 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 ("dd/MM/yyyy HH:mm:ss").parse("01/01/1970 01:00:00");
VBScript/ASP	DateDiff("s", "01/01/1970 00:00:00", time field)
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	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 these 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("dd/MM/yyyy HH:mm:ss").format(new java.util.Date (epoch*1000));
VBScript/ASP	DateAdd("s", epoch, "01/01/1970 00:00:00")
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';
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 timezones: =((A1 +/- timezone adjustment) / 86400) + 25569.
Crystal Reports	DateAdd("s", {EpochTimeStampField}-14400, #1/1/1970 00:00:00#) -14400 used for Eastern Standard Time. See Timezones.
JavaScript	use the JavaScript Date object
Unix/Linux	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.