On Mac Big Sur, how do I downgrade my version of Unision to a specific version?

Question

I’m running Mac OS 11.5.2 (Big Sur). I have the following version of unison installed using

brew install unison

Which is

$ unison -version
unison version 2.51.4 (ocaml 4.12.0)

However, in order to work with a virtual Ubuntu box, which runs

$ unison -version
unison version 2.51.2 (ocaml 4.08.1)

I need to downgrade my Mac OS version of Unison. But the brew command doesn’t give me control over the version. How do I downgrade my Mac version to match the Linux version?

Answer 1

# copy formula code
pbpaste > $(find $(brew --repository) -name <FORMULA>.rb)
brew install <FORMULA>

follow this blog https://remarkablemark.org/blog/2017/02/03/install-brew-package-version/

Answer 2

Brew is a rolling release package manager, which more or less by design does not let/want you to access previous versions.

If ditching brew is okay for you.

You can go directly to Unison's Github. On there you will be able to download the release you want Unison version 2.51.2 for OSX

Install should be very standard, unzip the file, drag the .app file to your application folder.

Answer 3

modify Unison's Formula code from this url Unison Formula and copy that then run command like that

# copy formula code
pbpaste > $(find $(brew --repository) -name unison.rb)
brew install unison