Get Current date in epoch from Unix shell script

Question

How to get the current date value in epoch i.e., number of days elapsed since 1970-1-1. I need solution in unix shell script.

Today 14,432 days have passed since the epoch. ;) http://www.timeanddate.com/date/durationresult.html?m1=1&d1=1&y1=1970&m2=&d2=&y2= — Stephan202, Jul 07 '09 at 19:29
Are you sure you want the number of _days_ since epoch? The answers so far give you seconds :) you'll need to divide that by 60 * 60 * 24 to get your answer :) — Jeremy Smyth, Jul 07 '09 at 19:29
thanks to all... but my system is not recognizing the +%s format specifier, am not getting the result :( — , Jul 07 '09 at 19:34
What kind of system are you on, then? Anyway, give the solution I posted below a try. Perhaps that script is more portable... — Stephan202, Jul 07 '09 at 19:54
Regarding @Stephan202's link, I find [Epoch Converter](http://www.epochconverter.com/) to be a richer source of information and tools than timeanddate.com. — Randall Cook, Nov 07 '11 at 22:51

score 172 · Answer 1 · edited Feb 15 '21 at 15:58

172

The Unix Date command will display in epoch time

the command is

date +"%s"

https://linux.die.net/man/1/date

Edit: Some people have observed you asked for days, so it's the result of that command divided by 86,400

edited Feb 15 '21 at 15:58

NKSM

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answered Jul 07 '09 at 19:36

UberAlex

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Note that `%s` is an extension. POSIX date does not have `%s`. See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html for details. – Jens Sep 01 '11 at 08:04
1

Not all days have 86400 seconds (DST, leap seconds, etc...) – Catfish_Man Jan 23 '13 at 08:19
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Again, in unix time (date +%s) each day has 86400 "seconds", it does not include leap seconds and certainly not DST. The answer is correct. – Sam Watkins Oct 23 '13 at 00:57
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Is it possible to display the milliseconds since the epoch? – Daniel Node.js Sep 06 '15 at 00:51
@DanielPendergast In Bash at least, `expr $(date +"%s") \* 1000`. – duozmo Feb 09 '16 at 21:06
That won't give you the actuall millisecond current time though (which I'm looking for in my performance profiling). – Sridhar Sarnobat Aug 28 '21 at 03:38

score 60 · Accepted Answer · edited May 23 '17 at 12:34

60

Update: The answer previously posted here linked to a custom script that is no longer available, solely because the OP indicated that date +'%s' didn't work for him. Please see UberAlex' answer and cadrian's answer for proper solutions. In short:

For the number of seconds since the Unix epoch use date(1) as follows:
```
date +'%s'
```
For the number of days since the Unix epoch divide the result by the number of seconds in a day (mind the double parentheses!):
```
echo $(($(date +%s) / 60 / 60 / 24))
```

edited May 23 '17 at 12:34

Community

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answered Jul 07 '09 at 19:35

Stephan202

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This is not the best answer, and no longer useful at all, as the links are broken. It should be a one liner, as below. – Sam Watkins Oct 23 '13 at 00:59
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@SamWatkins: Very much agreed. Unfortunately accepted answers cannot be deleted. – Stephan202 Oct 23 '13 at 12:44
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@alancnet: the answer was not incorrect for the OP, but he did have a very weird setup indeed. Anyway, I had enough of all the downvotes, so I rewrote the answer to something that is useful for the other 99.9999% of the planet. – Stephan202 Apr 14 '16 at 06:35

score 12 · Answer 3 · answered Jul 07 '09 at 19:30

12

echo $(($(date +%s) / 60 / 60 / 24))

answered Jul 07 '09 at 19:30

cadrian

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Note that `%s` is an extension. POSIX date does not have `%s`. See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/date.html for details. – Jens Sep 01 '11 at 08:05
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Not all days have 86400 (60*60*24) seconds (DST, leap seconds, etc...) – Catfish_Man Jan 23 '13 at 08:19
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Unix time does have 86400 seconds per day exactly. Note, if using with -d for a specific date, suggest -u for UTC, or answer will vary by timezone. echo $(( $(date -u -d '2014-01-01' +%s) / 86400 )) – Sam Watkins Oct 23 '13 at 00:56

score 2 · Answer 4 · answered Jul 07 '09 at 19:36

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echo `date +%s`/86400 | bc

answered Jul 07 '09 at 19:36

Chris Doggett

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Not all days have 86400 seconds (DST, leap seconds, etc...) – Catfish_Man Jan 23 '13 at 08:20

score -3 · Answer 5 · answered Jul 07 '09 at 19:27

-3

Depending on the language you're using it's going to be something simple like

CInt(CDate("1970-1-1") - CDate(Today()))

Ironically enough, yesterday was day 40,000 if you use 1/1/1900 as "day zero" like many computer systems use.

answered Jul 07 '09 at 19:27

mandroid

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That looks like VB to me. The question asks in relation to a Unix shell script. – Noldorin Jul 07 '09 at 19:32
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He edited it after I answered. Thanks for your input anyway. – mandroid Jul 07 '09 at 20:01

Get Current date in epoch from Unix shell script

5 Answers5

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