Migration strategy for a new mac

[mbierman]

Sorry for such a simple question...

I am getting a new mac for the first time in a long time and I am wondering what the best way to migrate all the things I have installed with homebrew is. I assume migration assistant won't bring it over? So is there a way of getting a list of homebrew packages and, ideally creating a script or manifest so I can just mirror the same packages on the new machine?

[nandahkrishna]

You might want to check out brew bundle: https://github.com/Homebrew/homebrew-bundle. With brew bundle dump you can create a Brewfile with a list of all packages you installed, and you can use this to install packages on your new Mac.

[gromgit]

It's generally a good idea to do fresh installs of existing software on a new system, especially if (I assume) you're moving from Intel to Apple Silicon.

First back up your old Mac, if you haven't already done so. (This is just a precautionary measure, in case the next step goes pear-shaped for some bizarre reason.)

Then on your old Mac:

# Get the latest Homebrew software
brew update
# Dump your existing Homebrew install state
brew bundle dump --global --force

Now go over to your new Mac, and use Migration Assistant to pull over everything it can. After it's done, check to see if $HOME/.Brewfile exists; if not, copy it over.

Next, install Homebrew afresh -- it should be writing to /opt/homebrew instead of /usr/local.

Finally, reinstall all your beloved formulae from fresh bottles:

brew bundle --global

You may have to wait a while, depending on how many formulae you'd previously installed.

[nandahkrishna]

/opt/homebrew is just for Apple Silicon. I assume your old machine has an Intel processor, so Homebrew will install into /usr/local.

[mbierman]

perfect, makes sense @nandahkrishna Thank you.

[mbierman]

One last question (I hope). My Brewfile looks like this (below). Why is brew "python@2", link: false and brew "git-ftp", link: false ? Should I change that to reinstall? I did a complete brew uninstall and reinstall and brew doctor says everything is good. Before I mess it up is there anything wrong with the Brewlist below?

tap "homebrew/bundle"
tap "homebrew/cask"
tap "homebrew/cask-drivers"
tap "homebrew/cask-fonts"
tap "homebrew/cask-versions"
tap "homebrew/core"
tap "ipinfo/tap"
tap "vitorgalvao/tiny-scripts"
brew "libssh2"
brew "curl"
brew "exiftags"
brew "fd"
brew "fswatch"
brew "gdbm"
brew "git-ftp", link: false
brew "grepip"
brew "iperf3"
brew "ipinfo-cli"
brew "jenv"
brew "jq"
brew "libxml2"
brew "python@2", link: false
brew "python@3.8"
brew "rsync"
brew "shellcheck"
brew "tag"
brew "tidy-html5"
brew "wakeonlan"
brew "wget"
brew "wireshark"
brew "vitorgalvao/tiny-scripts/cask-repair"
cask "aerial"
cask "blackhole-16ch"
cask "blackhole-2ch"
cask "keycastr"

[gromgit]

Why is brew "python@2", link: false and brew "git-ftp", link: false ? Should I change that to reinstall?

Either you ran brew unlink on these two formulae, or Homebrew did the equivalent for some reason (can't think of a reason why though). You can manually brew link those formulae, then:

mv ~/.Brewfile ~/.Brewfile.old
brew bundle dump --global

then compare Brewfile and Brewfile.old to see if anything else changed. I suggest this because...

is there anything wrong with the Brewlist below?

I don't see anything specifically "wrong" with your Brewfile, but assuming you haven't run brew bundle --global on your new Mac, you're guaranteed at least one error when you do: python@2 no longer exists. If any of the other formulae and casks have been deprecated, disabled or removed entirely, you'll get errors for those too.

That said, brew bundle --global shouldn't hurt anything; you just may not get everything back that you used to have. To borrow the opening line from a long-running soap: "Like sands though the hourglass, so are the formulae of Homebrew."

[SMillerDev]

brew "vitorgalvao/tiny-scripts/cask-repair"

This one is deprecated in favor of brew bump-cask-version. But I bet it won't break anything to install it.