Rebuilding reinstalling upgrading Go

• My Go source is in ~/.go, moved to ~/.go1.4 to make room for 1.5
• export GOROOT_BOOTSTRAP="/usr/local/go1.4" so all.bash knows where the Go it's building with is

/usr/local/go/src $ ./all.bash

1.6 ⇢ 1.9

• firstly get the location of Go (which go ⇒ /usr/local/go/bin/go)

• as outlined here, remove the existing Go (or if you like, keep it for posterity, or in case you need to roll back)

  sudo mv /usr/local/go/ /usr/local/go1.6/

• download the latest binary from golang.org

• sudo tar -C /usr/local -xzf Downloads/go1.9.2.linux-amd64.tar.gz

• to confirm, run go version ⇒ go version go1.9.2 linux/amd64