{"id":311,"date":"2012-02-22T00:00:00","date_gmt":"2012-02-22T00:00:00","guid":{"rendered":"http:\/\/www.scmgalaxy.com\/tutorials\/2012\/02\/22\/understanding-epoch-unix-timestamp\/"},"modified":"2017-12-27T17:51:07","modified_gmt":"2017-12-27T17:51:07","slug":"understanding-epoch-unix-timestamp","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/understanding-epoch-unix-timestamp\/","title":{"rendered":"How to Understand Epoch & Unix Timestamp | Epoch Converter"},"content":{"rendered":"

\"epoch-unix-timestamp\"<\/h2>\n

What is epoch time?<\/h2>\n

The Unix epoch<\/strong> (or Unix time<\/strong> or POSIX time<\/strong> or Unix timestamp<\/strong>) 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).<\/p>\n\n\n\n\n\n\n\n\n
Human readable time<\/strong><\/td>\nSeconds<\/strong><\/td>\n<\/tr>\n
1 hour<\/td>\n3600 seconds<\/td>\n<\/tr>\n
1 day<\/td>\n86400 seconds<\/td>\n<\/tr>\n
1 week<\/td>\n604800 seconds<\/td>\n<\/tr>\n
1 month (30.44 days)<\/td>\n2629743 seconds<\/td>\n<\/tr>\n
1 year (365.24 days)<\/td>\n31556926 seconds<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

How to get the current epoch time in …<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Perl<\/strong><\/td>\ntime<\/td>\n<\/tr>\n
PHP<\/strong><\/td>\ntime()<\/td>\n<\/tr>\n
Ruby<\/strong><\/td>\nTime.now (or Time.new). To display the epoch: Time.now.to_i<\/td>\n<\/tr>\n
Python<\/strong><\/td>\nimport time first, then time.time()<\/td>\n<\/tr>\n
Java<\/strong><\/td>\nlong epoch = System.currentTimeMillis()\/1000;<\/td>\n<\/tr>\n
Microsoft .NET C#<\/strong><\/td>\nepoch = (DateTime.Now.ToUniversalTime().Ticks – 621355968000000000) \/ 10000000;<\/td>\n<\/tr>\n
VBScript\/ASP<\/strong><\/td>\nDateDiff(“s”, “01\/01\/1970 00:00:00”, Now())<\/td>\n<\/tr>\n
R<\/strong><\/td>\nas.numeric(Sys.time())<\/td>\n<\/tr>\n
Erlang<\/strong><\/td>\ncalendar:datetime_to_gregorian_seconds(calendar:now_to_universal_time( now()))-719528*24*3600.<\/td>\n<\/tr>\n
MySQL<\/strong><\/td>\nSELECT unix_timestamp(now()) More info (+ negative epochs)<\/a><\/td>\n<\/tr>\n
PostgreSQL<\/strong><\/td>\nSELECT extract(epoch FROM now());<\/td>\n<\/tr>\n
Oracle PL\/SQL<\/strong><\/td>\nSELECT (SYSDATE – TO_DATE(’01\/01\/1970 00:00:00′, ‘MM-DD-YYYY HH24:MI:SS’)) *
\n24 * 60 * 60 FROM DUAL<\/td>\n<\/tr>\n
SQL Server<\/strong><\/td>\nSELECT DATEDIFF(s, ‘1970-01-01 00:00:00’, GETUTCDATE())<\/td>\n<\/tr>\n
JavaScript<\/strong><\/td>\nMath.round(new Date().getTime()\/1000.0) getTime() returns time in milliseconds.<\/td>\n<\/tr>\n
Tcl\/Tk<\/strong><\/td>\nclock seconds<\/td>\n<\/tr>\n
Unix\/Linux Shell<\/strong><\/td>\ndate +%s<\/td>\n<\/tr>\n
PowerShell<\/strong><\/td>\nGet-Date -UFormat “%s” Produces: 1279152364.63599<\/td>\n<\/tr>\n
Other OS’s <\/strong><\/td>\nCommand line: perl -e “print time” (If Perl is installed on your system)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Convert from human readable date to epoch<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Perl<\/strong><\/td>\nUse the Perl Epoch routines<\/a><\/td>\n<\/tr>\n
PHP<\/strong><\/td>\nmktime(hour<\/em>, minute<\/em>, second<\/em>, month<\/em>, day<\/em>, year<\/em>) \"More<\/a><\/td>\n<\/tr>\n
Ruby<\/strong><\/td>\nTime.local(year<\/em>, month<\/em>, day<\/em>, hour<\/em>, minute<\/em>, second<\/em>, usec<\/em> ) (or Time.gm for GMT\/UTC input). To display add .to_i<\/td>\n<\/tr>\n
Python<\/strong><\/td>\nimport time first, then int(time.mktime(time.strptime(‘2000-01-01 12:34:00’, ‘%Y-%m-%d %H:%M:%S’))) – time.timezone<\/td>\n<\/tr>\n
Java<\/strong><\/td>\nlong epoch = new java.text.SimpleDateFormat (“MM\/dd\/yyyy HH:mm:ss”).parse(“01\/01\/1970 01:00:00”).getTime();<\/td>\n<\/tr>\n
VBScript\/ASP<\/strong><\/td>\nDateDiff(“s”, “01\/01\/1970 00:00:00”, time field<\/em>) \"More<\/a><\/td>\n<\/tr>\n
C<\/strong><\/td>\nUse the C Epoch Converter routines<\/a><\/td>\n<\/tr>\n
R<\/strong><\/td>\nas.numeric(as.POSIXct(“MM\/dd\/yyyy HH:mm:ss”, origin=”1970-01-01″))<\/td>\n<\/tr>\n
MySQL<\/strong><\/td>\nSELECT unix_timestamp(time<\/em>) Time format: YYYY-MM-DD HH:MM:SS or YYMMDD or YYYYMMDD
\nMore on using Epoch timestamps with MySQL<\/a><\/td>\n<\/tr>\n
PostgreSQL<\/strong><\/td>\nSELECT extract(epoch FROM date(‘2000-01-01 12:34’));
\nWith timestamp: SELECT EXTRACT(EPOCH FROM TIMESTAMP WITH TIME ZONE ‘2001-02-16 20:38:40-08’);
\nWith interval: SELECT EXTRACT(EPOCH FROM INTERVAL ‘5 days 3 hours’);<\/td>\n<\/tr>\n
SQL Server<\/strong><\/td>\nSELECT DATEDIFF(s, ‘1970-01-01 00:00:00’, time field<\/em>)<\/td>\n<\/tr>\n
JavaScript<\/strong><\/td>\nUse the JavaScript Date object<\/a><\/td>\n<\/tr>\n
Unix\/Linux Shell<\/strong><\/td>\ndate +%s -d”Jan 1, 1980 00:00:01″ Replace ‘-d’ with ‘-ud’ to input in GMT\/UTC time.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Convert from epoch to human readable date<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Perl<\/strong><\/td>\nUse the Perl Epoch routines<\/a><\/td>\n<\/tr>\n
PHP<\/strong><\/td>\ndate(output format<\/em>, epoch<\/em>); Output format example: ‘r’ = RFC 2822 date \"More<\/a><\/td>\n<\/tr>\n
Ruby<\/strong><\/td>\nTime.at(epoch<\/em>)<\/td>\n<\/tr>\n
Python<\/strong><\/td>\nimport time first, then time.strftime(“%a, %d %b %Y %H:%M:%S +0000”, time.localtime(epoch<\/em>)) Replace time.localtime with time.gmtime for GMT time. \"More<\/a><\/td>\n<\/tr>\n
Java<\/strong><\/td>\nString date = new java.text.SimpleDateFormat(“MM\/dd\/yyyy HH:mm:ss”).format(new java.util.Date (epoch<\/em>*1000));<\/td>\n<\/tr>\n
VBScript\/ASP<\/strong><\/td>\nDateAdd(“s”, epoch<\/em>, “01\/01\/1970 00:00:00”) \"More<\/a><\/td>\n<\/tr>\n
C<\/strong><\/td>\nUse the C Epoch Converter routines<\/a><\/td>\n<\/tr>\n
R<\/strong><\/td>\nas.POSIXct(epoch, origin=”1970-01-01″)<\/td>\n<\/tr>\n
MySQL<\/strong><\/td>\nfrom_unixtime(epoch<\/em>, optional output format<\/em>) The default output format is YYY-MM-DD HH:MM:SS more …<\/a><\/td>\n<\/tr>\n
PostgreSQL<\/strong><\/td>\nPostgreSQL version 8.1 and higher: SELECT to_timestamp(epoch<\/em>); \"More<\/a> Older versions: SELECT TIMESTAMP WITH TIME ZONE ‘epoch’ + epoch<\/em> * INTERVAL ‘1 second’;<\/td>\n<\/tr>\n
Oracle PL\/SQL<\/strong><\/td>\nSELECT to_date(’01-JAN-1970′,’dd-mon-yyyy’)+(1326357743\/60\/60\/24) from dual
\nReplace 1326357743 with epoch.<\/td>\n<\/tr>\n
SQL Server<\/strong><\/td>\nDATEADD(s, epoch<\/em>, ‘1970-01-01 00:00:00’)<\/td>\n<\/tr>\n
Microsoft Excel<\/strong><\/td>\n=(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<\/a>) \/ 86400) + 25569.<\/td>\n<\/tr>\n
Crystal Reports<\/strong><\/td>\nDateAdd(“s”, {EpochTimeStampField}-14400, #1\/1\/1970 00:00:00#) -14400 used for Eastern Standard Time. See Time Zones<\/a>.<\/td>\n<\/tr>\n
JavaScript<\/strong><\/td>\nUse the JavaScript Date object<\/a><\/td>\n<\/tr>\n
Tcl\/Tk<\/strong><\/td>\nclock format 1325376000 \"More<\/a><\/td>\n<\/tr>\n
Unix\/Linux Shell<\/strong><\/td>\ndate -d @1190000000 Replace 1190000000 with your epoch, needs recent version of ‘date’. Replace ‘-d’ with ‘-ud’ for GMT\/UTC time.<\/td>\n<\/tr>\n
PowerShell<\/strong><\/td>\nFunction get-epochDate ($epochDate) { [timezone]::CurrentTimeZone.ToLocalTime(([datetime]’1\/1\/1970′).AddSeconds($epochDate)) }, then use: get-epochDate 1279152364. Works for Windows PowerShell v1 and v2<\/td>\n<\/tr>\n
Other OS’s<\/strong><\/td>\nCommand line: perl -e “print scalar(localtime(epoch<\/em>))” (If Perl is installed) Replace ‘localtime’ with ‘gmtime’ for GMT\/UTC time.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Reference<\/strong><\/p>\n

http:\/\/www.epochconverter.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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…<\/p>\n","protected":false},"author":1,"featured_media":3849,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","_joinchat":[],"footnotes":""},"categories":[2],"tags":[2587,2588,2580,2582,2592,2583,2589,2590,2591,2581,2579,2586,169,2593,2584,2585],"class_list":["post-311","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorised","tag-about-epoch-timestamp","tag-about-unix-timestamp","tag-epoch","tag-epoch-and-unix","tag-epoch-converter","tag-epoch-time","tag-introduction-epoch-timestamp","tag-introduction-unix-timestamp","tag-overview-epoch-unix-timestamp","tag-timestamp","tag-understand","tag-understand-epoch-unix-timestamp","tag-unix","tag-unix-timestamp","tag-what-is-epoch-time","tag-what-is-unix-time"],"_links":{"self":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/311","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/comments?post=311"}],"version-history":[{"count":3,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/311\/revisions"}],"predecessor-version":[{"id":4334,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/posts\/311\/revisions\/4334"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media\/3849"}],"wp:attachment":[{"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/media?parent=311"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/categories?post=311"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.devopsschool.com\/blog\/wp-json\/wp\/v2\/tags?post=311"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}