This post is brought to you by 30 minutes of frustration. I hope it saves you some time.

7z is a is not a native file type on mac. In order to open it, you will need to install a 3rd party application. I chose p7zip because I can manage it using homebrew.

Install p7zip

Install via homebrew:

brew install p7zip

Unzip a File

IMPORTANT: be in the SAME directory on your command line as the file you want to extract. If the file is on your desktop, be in the desktop on your command line. <— THIS is the thing that tripped me up.

# ex file location:  /Users/yourusername/Desktop/compressed_file.7z

# cd into the correct location
cd ~/Desktop

# unzip the file
7z x compressed_file.7z

This will add a folder of unzipped files to that location, in this case, my Desktop.

Compress Files or Folder

To zip, use the a argument followed by output filename and by the files/folder you want to compress. Again, ensure you’re in the same directory on the command line as your input file.

7z a compressed_file.7z folder_to_compress

You can see more compression options on the app manual page by running:

man 7z