Homebrew & Pinning Versions

I recently started using Tomcat for a project I’m working on. Since I work on a Mac and am using Homebrew anyway, the installation was as easy:

brew install tomcat

The location of the installed files is /usr/local/Cellar/tomcat on a Mac, BTW. Now, occasionally and out of habit, I run this:

brew update && brew upgrade && brew cleanup

I prefer (usually) small issues with small version jumps to upgrading rarely with bigger version changes (and issues). Also cleaning up seems a good idea, not only on the working desk or kitchen sink.

This time, though, the upgrade removed the previously installed version of Tomcat — including stuff that I had put into a sub folder of the location given above. Not only was the Tomcat installation upgraded, but everything I’ve put in there was gone. 😳

Lesson No. 1: Maybe I shouldn’t have put the stuff there in the first place.
Lesson No. 2: Learn how to pin a version of installed software, when using Homebrew.

It’s easy. Use, for example

brew pin tomcat

to, well, pin the tomcat version. To find out later, when you want to upgrade a piece of software and wonder why it does not happen, use

brew list --pinned

to find out, what software is pinned. Last but not least, a package can be unpinned using:

brew unpin <package_name>

Reading the Homebrew FAQ is also a good idea.