go语言：一些环境变量

直接不翻译了

The Go compilation environment can be customized by environment variables. None is required by the build, but you may wish to set some to override the defaults.

• $GOROOT

  The root of the Go tree, often $HOME/go. Its value is built into the tree when it is compiled, and defaults to the parent of the directory where all.bash was run. There is no need to set this unless you want to switch between multiple local copies of the repository.

• $GOROOT_FINAL

  The value assumed by installed binaries and scripts when $GOROOT is not set explicitly. It defaults to the value of $GOROOT. If you want to build the Go tree in one location but move it elsewhere after the build, set $GOROOT_FINAL to the eventual location.

• $GOOS and $GOARCH

  The name of the target operating system and compilation architecture. These default to the values of$GOHOSTOS and $GOHOSTARCH respectively (described below).

  Choices for $GOOS are darwin (Mac OS X 10.6 and above), dragonfly, freebsd, linux, netbsd, openbsd, plan9,solaris and windows. Choices for $GOARCH are amd64 (64-bit x86, the most mature port), 386 (32-bit x86), and arm (32-bit ARM). The valid combinations of $GOOS and $GOARCH are:

  	$GOOS	$GOARCH
  	darwin	386
  	darwin	amd64
  	dragonfly	386
  	dragonfly	amd64
  	freebsd	386
  	freebsd	amd64
  	freebsd	arm
  	linux	386
  	linux	amd64
  	linux	arm
  	netbsd	386
  	netbsd	amd64
  	netbsd	arm
  	openbsd	386
  	openbsd	amd64
  	plan9	386
  	plan9	amd64
  	solaris	amd64
  	windows	386
  	windows	amd64

• $GOHOSTOS and $GOHOSTARCH

  The name of the host operating system and compilation architecture. These default to the local system's operating system and architecture.

  Valid choices are the same as for $GOOS and $GOARCH, listed above. The specified values must be compatible with the local system. For example, you should not set $GOHOSTARCH to arm on an x86 system.

• $GOBIN

  The location where Go binaries will be installed. The default is $GOROOT/bin. After installing, you will want to arrange to add this directory to your $PATH, so you can use the tools. If $GOBIN is set, the go command installs all commands there.