Returns the number of seconds since January 1st, 1970, Midnight, in Greenwich (GMT). Also known as "Unix time", "timestamp" or "epoch".

Example:

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clock seconds
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on `Dec 10, 2004 11:44:22 AT`, returns

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1102686262
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**Epoch**

[LV] Is the epoch the same on all platforms and operating systems?

[KBK] - If it isn't, that's a bug.  The epoch is 1970-01-01T00:00:00Z - that is, 00:00 UTC at the start of 1 January 1970.
It was once true that MacOS9 and below used a different epoch, but that proved to be too confusing for everyone.

[bll] 2015-2-14  The epoch on DOS (and the FAT* filesystems) was 1980-01-01.  [clock seconds] returns the seconds since 1970, so it has very nice cross platform compatibility.   Congrats to whoever did that.  Apparently Windows has an epoch starting in 1601. http://en.wikipedia.org/wiki/System_time%|%Wikipedia: System Time%|%

[RS]: Find out what your epoch is, without timezone offset, with
 clock format 0 -gmt 1

**Remainder of today**

[AMG]: To find how many seconds are left in the current day (strictly using UTC day starts), try:

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expr {86400 - [clock seconds] % 86400}
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This math works despite the existence of leap seconds because Tcl days are always 86400 seconds long, yet Tcl seconds are slightly longer than true for "some minutes" following a leap second.  Should a negative leap second ever occur, Tcl seconds would be slightly shorter to compensate.  To date (2019), 27 positive leap seconds have occurred and 0 negative leap seconds, plus another 10 positive leap seconds between TAI (atomic time) and UTC at the start of 1972.  So odds are good we'll never have a negative leap second.

See also [https://wiki.tcl-lang.org/page/clock+scan#4a8e1a3db846400c341130b85c48fa3c6d3f1fc2845e9f9b99d6167995b77d13%|%clock scan%|%] for an alternate method that is capable of working in timezones other than UTC.

**See also**

   * [clock]

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