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How do I get the current Unix time in milliseconds (i.e number of milliseconds since Unix epoch January 1 1970)?

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8 Answers 8

up vote 72 down vote accepted

This:

date +%s 

will return the number of seconds since the epoch.

This:

date +%s%N

returns the seconds and current nanoseconds.

So:

date +%s%N | cut -b1-13

will give you the number of milliseconds since the epoch - current seconds plus the left three of the nanoseconds.


and from MikeyB - echo $(($(date +%s%N)/1000000)) (dividing by 1000 only brings to microseconds)

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11  
I wonder how many ms the cut adds :-) –  Kyle Brandt Jun 14 '10 at 16:23
2  
I think seconds * 1000 will be fine :) –  Richard Jun 14 '10 at 16:34
8  
Or if you want to do it all in the shell, avoiding the expensive overhead of an additional process (actually, we're avoiding the problem when the number of digits in %+s+N changes): echo $(($(date +%s%N)/1000)) –  MikeyB Jun 14 '10 at 16:38
1  
It's the principle of the matter... avoid magic numbers and code what you actually mean. –  MikeyB Jun 14 '10 at 18:02
1  
I think it's worth noting that the man asked for Unix, not Linux, and the current top answer (date +%s%N) doesn't work on my AIX system. –  Pete Oct 25 '11 at 16:52
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Just throwing this out there, but I think the correct formula with the division would be:

echo $(($(date +%s%N)/1000000))
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Here is how to get time in milliseconds without performing division. Maybe it's faster...

# test=`date +%s%N`
# testnum=${#test}
# echo ${test:0:$testnum-6}
1297327781715

Update: Another alternative in pure bash that works only with bash 4.2+ is same as above but use printf to get the date. It will definitely be faster because no processes are forked off the main one.

printf -v test '%(%s%N)T' -1
testnum=${#test}
echo ${test:0:$testnum-6}

Another catch here though is that your strftime implementation should support %s and %N which is NOT the case on my test machine. See man strftime for supported options. Also see man bash to see printf syntax. -1 and -2 are special values for time.

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My solution is not the best but worked for me.

date +%s000

I just needed to convert a date like 2012-05-05 to milliseconds.

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date +%N doesn't work on OS X, but you could use ruby -e 'puts Time.now.to_f' or python -c 'import time; print time.time()'.

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for completeness... node -e 'console.log(Date.now())' –  slf Oct 10 '13 at 18:06
    
Using PHP: php -r 'echo microtime(TRUE);' –  TachyonVortex Nov 22 '13 at 16:41
    
Sure, you just have to wait for those interpreters to warm up. This works, too: wget -qO- http://www.timeapi.org/utc/now?\\s.\\N –  Camilo Martin Jun 23 at 13:26
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If you are looking for a way to display the length of time your script ran, the following will provide a (not completely accurate) result:

As near the beginning of your script as you can, enter the following

basetime=$(date +%s%N)

This'll give you a starting value of something like 1361802943996000000

At the end of your script, use the following

echo "runtime: $(echo "scale=3;($(date +%s%N) - ${basetime})/(1*10^09)" | bc) seconds"

which will display something like

runtime: 12.383 seconds

Notes:

(1*10^09) can be replaced with 1000000000 if you wish

"scale=3" is a rather rare setting that coerces bc to do what you want. There are lots more!

I only tested this on Win7/MinGW... I don't have a proper *nix box to hand.

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or you could just use time <script> –  warren Apr 25 at 13:32
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You may simply use %3N to truncate the nanoseconds to the 3 most significant digits (which then are milliseconds):

$ date +%s%3N
1397392146866

This works e.g. on my kubuntu 12.04.

But be aware, that %N may not be implemented depending on your target system. E.g. tested on an embedded system (buildroot rootfs, compiled using a non-HF arm cross toolchain) there was no %N:

$ date +%s%3N
1397392146%3N

(And also my (non rooted) Android tablet has no %N).

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For the people that suggest running external programs to get the milliseconds... at that rate, you might as well do this:

wget -qO- http://www.timeapi.org/utc/now?\\s.\\N

Point being: before picking any answer from here, please keep in mind that not all programs will run under one whole second. Measure!

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