How do I make a "Days until (date)" thing?

[SirManGuy_PersonDude]

Does anyone know how to make something that does math based off the date time? For example: I want it to tell me how many days until March 20th 2020 whenever prompted to do so. Any ideas?

[tjluoma]

I'm sure there are lots of way to do this, but here's how I'd do it…

zsh has built-in functionality for strftime which can definitely do this.

First step would be to find the Unix Epoch Seconds for the time that you want to measure to …

Let's say that you want to measure to 12:00 noon on 2020-03-20, you'd use this:

#!/bin/zsh -f

zmodload zsh/datetime

strftime -r "%Y-%m-%d %H:%M" "2020-03-20 12:00"

exit 0

which will output 1584720000 but let's save it to a variable instead… how about $TARGET?

And we need to get the current time, also in Unix Epoch Seconds. We use "$EPOCHSECONDS" for that. Then we just need to subtract one from the other. So it would look like this:

#!/bin/zsh -f

zmodload zsh/datetime

TARGET=$(strftime -r "%Y-%m-%d %H:%M" "2020-03-20 12:00")

DIFF=$(($TARGET - $EPOCHSECONDS))

exit 0

Now the variable $DIFF contains the number of seconds from right now until noon on 2020/03/20. But I assume you would that translated to something a bit more "readable". That's where seconds2readable.sh comes in.

#!/bin/zsh -f

zmodload zsh/datetime

TARGET=$(strftime -r "%Y-%m-%d %H:%M" "2020-03-20 12:00")

DIFF=$(($TARGET - $EPOCHSECONDS))

seconds2readable.sh "$DIFF"

exit 0

As I write this, the script tells me the answer is 175 days 12 hours 29 minutes 45 seconds.

So, how do you use this?

• Download seconds2readable.sh and put it somewhere like /usr/local/bin/seconds2readable.sh

• Note: if you don't have a /usr/local/bin/ folder, you can create it with this command:

sudo mkdir -p /usr/local/bin/
sudo chown "$USER" /usr/local/bin/

Use this command to download it:

curl -fL --output /usr/local/bin/seconds2readable.sh \
'https://gist.github.com/tjluoma/bb2b3d1c58e52576d61ce11221b8906a#file-seconds2readable-sh'

Now make it executable:

chmod 755 /usr/local/bin/seconds2readable.sh

Then you can put this into Keyboard Maestro. Note that I have added a $PATH line to the script because otherwise Keyboard Maestro might not check /usr/local/bin:

#!/bin/zsh -f

PATH=/usr/local/sbin:/usr/local/di:/usr/local/scripts:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/opt/X11/bin

zmodload zsh/datetime

TARGET=$(strftime -r "%Y-%m-%d %H:%M" "2020-03-20 12:00")

DIFF=$(($TARGET - $EPOCHSECONDS))

seconds2readable.sh "$DIFF"

exit 0

Put that script into Keyboard Maestro and tell it to output to a window or "display briefly" and I think you'll be all set. Just have to decide how you want to trigger it.

If you want to change it to work for another date, just change the 2020-03-20 part of the TARGET= line. You can also change the time. Just remember to use 24-hour time, so, for example, if you wanted to measure until 4:35pm, you'd use 16:35.

[Sleepy]

@tjluoma

I'm sure there are lots of way to do this, but here's how I'd do it…

TJ, I think there's a builtin token in KM that supports date math.

[peternlewis]

Use the functions:

• TIME function
• YEAR function
• MONTH function
• DAY function

to get the different in seconds, then divide by 24 and 3600.

(TIME(2020,3,20)-TIME(YEAR(),MONTH(),DAY()))/24/3600

[SirManGuy_PersonDude]

Works well, tysm. Just what I was looking for, peter.

[tjluoma]

Well, dang… I didn't know Keyboard Maestro could do that. Learned my new thing for the day.

[MartinPacker]

One of the answers mentioned zsh. I know this is the default in Catalina - which I’m not running yet - but is zsh installed by default in eg Mojave?

And yes I prefer the KM answer.