When yo installed a .pkg file on your mac, the question is how to remove it again.

Here's how to do it (using Go as an example).

We start with listing the installed packages:

$ pkgutil --pkgs

For Go, the package name is org.golang.go

Then we can inspect which files the package installed by executing:

$ pkgutil --files org.golang.go
etc
etc/paths.d
etc/paths.d/go
usr
usr/local
usr/local/go
...
usr/local/go/test/varinit.go
usr/local/go/test/winbatch.go
usr/local/go/test/writebarrier.go
usr/local/go/test/zerodivide.go

As you can see, these paths are relative, not absolute. They are relative to the install location of the package. To get the install location of the package, you can execute:

$ pkgutil --pkg-info org.golang.go
package-id: org.golang.go
version: go1.16beta1
volume: /
location: /
install-time: 1608468554

As they are installed in the root, we first need to go to that directory. This is important as the remaining commands use the relative paths to this location.

$ cd /

Beware! Modifying the filesystem with root privileges can be hazardous.

We can then start with removing the actual files:

$ pkgutil --only-files --files org.golang.go | tr '\n' '\0' | xargs -n 1 -0 sudo rm -f

Then, we can also remove all empty directories with:

$ pkgutil --only-dirs --files org.golang.go | tail -r | tr '\n' '\0' | xargs -n 1 -0 sudo rmdir

Note that we are using the rmdir command here instead of rm -r. The rmdir command only removes the folders if they are empty. We want to keep the non-empty folders as there are folders in the list which are shared between different applications (e.g. the /usr/local folder which you don't want to remove).

The last step is to make the system forget that the package was installed:

$ sudo pkgutil --forget org.golang.go

Before you execute this, please be aware that if you don't use the commands correctly, you might bring your system into an unusable state, so proceed with caution.