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

Answer 1

Alternatively you can install GNU date like so:

1. install Homebrew: https://brew.sh/
2. brew install coreutils
3. add to your bash_profile: alias date="/usr/local/bin/gdate"
4. 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.