I use Mac Big Sur 11.5.1. I installed wget using brew, but the terminal said apt-get: command not found when I put sudo apt-get install ros-noetic-imu-tools. Although I tried brew install wget again, it said wget 1.21.1 is already installed and up-to-date. So wget is installed for sure. What is a possible cause?
macOS doesn't use apt as its package manager. Homebrew is the most popular package manager for macOS. Additionally, wget is a separate software package than the package manager, apt. See the awesome answer here for more information.
I would try this search for getting it ROS working with Mac. This SO question might be of relevance too.