Extensions must go in ~/.vscode/extensions according to the docs - that’s where other marketplace extensions go as directories.

Install from path

Run this against an a locally built or downloaded .vsix package file. This will unzip your built package and move it to the appropriate directory.

$ code --install-extension EXTENSION_PATH

Sample result:

Installing extensions...
Extension 'auto-commit-msg-0.6.0.vsix' was successfully installed.

You can verify it was unzipped and moved to here:

$ ls ~/.vscode/extensions/

dbaeumer.vscode-eslint-2.1.8      michaelcurrin.auto-commit-msg-0.6.0

Then restart VS Code.

You can even do this while VS Code is running. You can check @installed in your extensions tab and it can refresh to show the latest version under the same name. But you might get “Reload Required” notice so it’s a good idea to click that or restart VS Code another way.

Install from ID

If published, you can also install by providing the extension ID from the marketplace for the command above.

$ code --install-extension MARKETPLACE_EXTENSION_ID

Then restart VS Code.

Install within VS Code

There is also the ext syntax you’ll see in the marketplace, which can be used to the command prompt within VS Code, rather than using the terminal.