Go-如何按照go-ui的指示安装软件包

Trying to use https://github.com/visualfc/go-ui, but the following step is failing.

C:\>go get github.com/visualfc/go-ui
package github.com/visualfc/go-ui: cannot download, $GOPATH not set. For more de
tails see: go help gopath

or

$ go get github.com/visualfc/go-ui
can't load package: package github.com/visualfc/go-ui: no Go source files in /usr/lib/go/src/pkg/github.com/visualfc/go-ui

From the example in the readme, you should go get the package as per what is imported, which in this case is:

import (
    "github.com/visualfc/go-ui/ui"
)

To get that package, use this command:

go get github.com/visualfc/go-ui/ui