How to convert DATE to UNIX TIMESTAMP in shell script on MacOS

Question

On Linux you can convert a date like "2010-10-02" to a unix timestamp in shell script by

date -d "2010-10-02" "+%s"

Since Mac OS does not have the equivalent -d for date. How do you go about converting a date to a unix timestamp in a shell script.

JRiggles · Accepted Answer · 2012-02-18 05:58:12Z

143

date +%s

This works fine for me on OS X Lion.

answered Feb 18, 2012 at 5:58

JRiggles

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2 Comments

Irfan Over a year ago

Works in Linux as well (Ubuntu 10.04)

luator Over a year ago

OP asks about converting a specific given date to a timestamp. date +%s will just use the current date.

Lou Franco · Accepted Answer · 2010-09-28 23:38:02Z

45

man date on OSX has this example

date -j -f "%a %b %d %T %Z %Y" "`date`" "+%s"

Which I think does what you want.

You can use this for a specific date

date -j -f "%a %b %d %T %Z %Y" "Tue Sep 28 19:35:15 EDT 2010" "+%s"

Or use whatever format you want.

answered Sep 28, 2010 at 23:38

Lou Franco

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Learner Over a year ago

ON OSX Terminal using bash shell I am unable to use the above command Ex: currDate=date +%Y%m%d date -j -f "%a %b %d %T %Z %Y" "${currDate}" "+%s"

linuxeasy Over a year ago

@Jagdeep This'd work on OSX only if the Timezone specified is that of system's timezone. I am in PDT so in the above command, changing EDT wtih PDT worked for me.

user405725 · Accepted Answer · 2010-09-28 23:43:31Z

18

date -j -f "%Y-%m-%d" "2010-10-02" "+%s"

answered Sep 28, 2010 at 23:43

user405725

2 Comments

Drew Daniels Over a year ago

This generates a different Unix Timestamp every time you run it though, which I don't think is what you want

Flo Apr 22 at 15:56

@DrewDaniels True! Quote from the man: "Note that any date or time components unspecified by the -f format string take their values from the current time." So as the hours, minutes, and seconds are absent from this -f format, they are taken from the current time, which explains why you get a different result at each run with this command. The correct answer using this method should be date -j -f "%Y-%m-%d %H:%M:%S" "2010-10-02 00:00:00" "+%s"

vanyo · Accepted Answer · 2020-04-07 09:47:13Z

5

date -j -f "%Y-%m-%d %H:%M:%S" "2020-04-07 00:00:00" "+%s"

It will print the dynamic seconds when without %H:%M:%S and 00:00:00.

answered Apr 7, 2020 at 9:47

vanyo

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ma11hew28 Over a year ago

Nice, thanks. If you man strftime, you'll see that "%F is equivalent to %Y-%m-%d" and "%T is equivalent to %H:%M:%S". So I think you can shorten your input_fmt to "%F %T" if you'd like.

Drew Daniels Over a year ago

This is the only thing that worked for my use case - the other answers weren't idempotent and generated different Unix timestamps on each run, because the hours, minutes, and seconds were being used from the current date.

smarisetti · Accepted Answer · 2014-05-15 21:25:16Z

4

I used the following on Mac OSX.

currDate=`date +%Y%m%d`
epochDate=$(date -j -f "%Y%m%d" "${currDate}" "+%s")

answered May 15, 2014 at 21:25

smarisetti

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Scott Prive · Accepted Answer · 2019-08-20 14:20:30Z

Alternatively you can install GNU date like so:

install Homebrew: https://brew.sh/
brew install coreutils
add to your bash_profile: alias date="/usr/local/bin/gdate"
date +%s 1547838127

Comments saying Mac has to be "different" simply reveal the commenter is ignorant of the history of UNIX. macOS is based on BSD UNIX, which is way older than Linux. Linux essentially was a copy of other UNIX systems, and Linux decided to be "different" by adopting GNU tools instead of BSD tools. GNU tools are more user friendly, but they're not usually found on any *BSD system (just the way it is).

Really, if you spend most of your time in Linux, but have a Mac desktop, you probably want to make the Mac work like Linux. There's no sense in trying to remember two different sets of options, or scripting for the mac's BSD version of Bash, unless you are writing a utility that you want to run on both BSD and GNU/Linux shells.

ma11hew28 · Accepted Answer · 2021-03-08 14:56:24Z

1

To convert a date in UTC to a Unix timestamp:

date -ju -f "%F %T" "2021-03-08 14:56:21" "+%s"

answered Mar 8, 2021 at 14:56

ma11hew28

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alex · Accepted Answer · 2021-01-30 12:29:59Z

I wrote a set of scripts that provides a uniform interface for both BSD and GNU version of date.

Follow command will output the Epoch seconds for the date 2010-10-02, and it works with both BSD and GNU version of date.

$ xsh /date/convert "2010-10-02" "+%s"
1286020263

It's an equivalent of the command with GNU version of date:

date -d "2010-10-02" "+%s"

and also the command with BSD version of date:

date -j -f "%F" 2010-10-02 "+%s"

The scripts can be found at:

https://github.com/xsh-lib/core/tree/master/functions/date

It's a part of a library called xsh-lib/core. To use them you need both repos xsh and xsh-lib/core, I list them below:

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