Show HN: A Unix timestamp converter that includes the micro and nanoseconds | Hacker News Reader

Show HN: A Unix timestamp converter that includes the micro and nanoseconds

justquickmath.com

27 pointssurfingninja26 comments

I find myself having to convert a lot of unix timestamps to a human readable format, but most of the online calculators I found don't include the micro or nanoseconds in the human readable output. It's a small detail, but I find myself having to manually space out the timestamp frequently. I'm learning frontend development, so I made this converter to hopefully make it easier to convert timestamps. Welcome to any feedback :)

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Reminds me of a call I was on a few weeks ago where someone went off that Unix epoch with milliseconds wasn’t the Unix epoch. Made it a huge point that it wasn’t and would correct everyone who tried to refer to it as that. I did Google it and he technically is right. But it’s also a stupid hill to die on.

Your colleague is absolutely correct. That was the same objection I had to this. Unix timestamp format is only seconds. This page shows a timestamp but not a Unix timstamp, so the hill people are dying on here is to take and reuse a name for a different format out of their own stubborness - even after they learned they are wrong. It's very confusing and rejected by tools that only work with unix timestamps.

That said, this appears like a very minor point, but it's not. This is how bugs are created.

exactly. people using milliseconds and calling it a unix timestamp are wrong. provably wrong. so for them to dig in, or anything other than say "oh you are right, sorry", is just a waste of everyone's time. Accept that you made a mistake, and move on.

I added a comment to this effect at https://gist.github.com/timvisee/fcda9bbdff88d45cc9061606b4b...

I'll contact the original author as well. This is definitely an issue that should be listed in "falsehoods that programmers believe about time".

Doesn't 'date' do this on the commabd line?

gdate if you’re using home brew on Mac

date +'%F %H:%M:%S.%N' -d @1677954553.2134567654

Adjust the format as desired.

Or if there is the number of nsecs rather than the fraction:

date +'%F %H:%M:%S.%N' -d @$(dc -e '9k 16779545532134567654 10 9^/p')

The dc stuff is RPN, k sets the precision, p is print.

I got in the habit of using %T for Time (of day), as a shorthand for %H:%M:%S, but I can't recall how portable that is.

  date "+%F %T.%N"

If you stopped people from posting about their amazing new project that replicates standard functionality from classic unix tools we'd have very little left.

Cool. Let’s stop people from discussing these ‘amazing’ projects then. That sounds productive.

Mate, I'm very confused.

The first result in Google [1] which I often use, lets me paste a unix timestamp in seconds, milliseconds or nano seconds, and it accordingly converts it to a Human readable string.

Is that not the feature you built this for?

[1] - https://www.epochconverter.com/

Take the timestamp "1677951565000123456" for example - If I put it into the link you posted, it just gives me "Saturday, March 4, 2023 11:39:25 AM". While it's a minor drawback, it requires another step to figure out the microsecond and nansecond part of the timestamp since it's not in the output. My website would display "Saturday March 3 2023 11:39:25.000,123,456 AM -06:00 (nanos)", which gives you "000,123,456" telling you the milli,micro,nano breakdown of the timestamp

> Take the timestamp "1677951565000123456" for example - If I put it into the link you posted, it just gives me "Saturday, March 4, 2023 11:39:25 AM"

It looks like it only gives millisecond resolution in the output, and only displays milliseconds if there is at least 1 millisecond. Give it 1677951565020123456 and then you will get 11:39:25.020.

Exactly. I've been using epoch converter for years. It's the first thing that comes up in search results too.

How did this reach the front page?

See my other response to the parent for the reason I felt there was room to improve on the existing websites. Are there any other features you would find useful in a timestamp converter?

As someone involved in a lot of hiring, it's very common especially for junior developers (which OP appears to be) to pad their resumes with many toy web apps that effectively wrap or replicate simple Unix tools. I have noticed this trend a lot in the last year or two. It does give those applicants a leg up for sure, especially in this market, but do only take these projects at face value.

At the same time, we celebrate rewriting small Unix tools in Rust. How is that different?

You shouldn't view someone building a toy project in a negative light, even if it's for learning purposes. It demonstrates curiosity and interest in learning, and is part of what being a hacker is all about.

Maybe it's not frontpage worthy for this crowd, but it's certainly worth mentioning in a CV, especially for junior engineers. It can serve as a good topic of discussion during the interview, for example.

Wait, so it determines the units based on the actual number? This is really bad!

I got something incorrect, inputting 1777777777 gave me sunday may 5 2026 but that day is a tuesday

Thank you for the feedback! I identified the root cause of the bug and uploaded a fixed version.

Looks like you have varying precision with date, might be using floating point?

What do you mean by varying precision? Do you have an example? Thanks

At first I didn't understand the input format, which seems to try and autodetect the units.

When I enter 1e-3, I get 1ms past epoch start, but 1e-4 is 0ms past epoch start. And that isn't what I'd expect.

Here's another odd one, or why I wonder what internal precision things are calculated to:

1234567800000000090.000 is Friday February 2 2009 11:30:00.000,90.,000 PM +00:00 (nanos)

But 1234567800000000090.0001 is Friday February 2 2009 11:30:00.000,0.0,001 PM +00:00 (nanos)

Arguably, UNIX time was really just seconds, but it is handy to have more precision, it just didn't always align with what I'd expect.

Thanks for the feedback! I will make sure to fix those edge cases with fractional nanosecond values

I recommend CyberChef for this kind of utilities.

here is some Go code that does the same thing:

    package unix
    
    import "time"
    
    // 2023-03-04 11:35:43.4859519 -0600 CST
    func unix_nano(nsec int64) string {
       return time.Unix(0, nsec).String()
    }

https://godocs.io/time#Unix

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