How to Set Date Time from Mac Command Line
Working on a web extension that ships to an app store and isn't immediately modifiable, like a website, can be difficult. Since you cannot immediately deploy updates, you sometimes need to bake in hardcoded date-based logic. Testing future dates can be difficult if you don't know how to quickly change the date on your local machine.
To change the current date on your Mac, execute the following from command line:
# Date Format: MMDDYYYY
sudo date -I 06142024
This command does not modify time, only the current date. Using the same command to reset to current date is easy as well!
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I didn’t understand your exact use case, but a helpful way to do date-related testing without modifying your actual computer date/time, is to shim the system calls with library pre-loading. On a Mac, dyld can do this with DYLD_LIBRARY_PATH. On Linux, GNU ld can do it with LD_LIBRARY_PATH.
This makes it easy to write tests for specific situations, such as monthly changeovers, leap-occurrences, timezones, etc.
“libfaketime” is a handy library written for this, https://github.com/wolfcw/libfaketime. It’s even packaged in homebrew, just do
brew install libfaketime. :)