有新的Go版本出来后，我们通常使用go install来进行安装，我们以安装go 1.18 beta 2版本为例进行说明。
使用go install安装go1.18beta2的最新版本
go install golang.org/dl/go1.18beta2@latest执行这条命令的结果是会下载go1.18beta2这个可执行程序文件到本地，那会有几个疑问：
go1.18beta2可执行文件存放在哪里？go1.18beta2要怎么使用？go1.18beta2的源码存放在哪里？即go1.18beta2的GOROOT路径是什么？go1.18beta2的GOPATH路径是什么？
go install [build flags] [packages]Install compiles and installs the packages named by the import paths.
Executables are installed in the directory named by the GOBIN environment variable, which defaults to $GOPATH/bin or $HOME/go/bin if the GOPATH environment variable is not set. Executables in $GOROOT are installed in $GOROOT/bin or $GOTOOLDIR instead of $GOBIN.
-
如果设置了
GOPATH环境变量，go1.18beta2会安装到$GOPATH/bin目录下 -
如果没有设置
GOPATH环境变量，go1.18beta2会安装到$HOME/go/bin目录下
一般都会设置GOPATH环境变量，可以使用如下命令查看GOPATH的值
go env GOPATH安装完之后可以去对应目录查看是否存在go1.18beta2 文件。
通过上面go install下载到的go1.18beta2可执行文件其实还不能直接使用。
比如执行go1.18beta2 version命令，会得到如下结果：
go1.18beta2: not downloaded. Run 'go1.18beta2 download' to install to /Users/xxx/sdk/go1.18beta2因此还要使用go1.18beta2 download下载go1.18beta2版本的源码。
$ go1.18beta2 download
Downloaded 0.0% ( 16384 / 143466224 bytes) ...
Downloaded 0.3% ( 360448 / 143466224 bytes) ...
Downloaded 2.8% ( 3964912 / 143466224 bytes) ...
Downloaded 5.4% ( 7798736 / 143466224 bytes) ...
Downloaded 7.9% ( 11321264 / 143466224 bytes) ...
Downloaded 10.8% ( 15531952 / 143466224 bytes) ...
Downloaded 14.3% ( 20479856 / 143466224 bytes) ...
Downloaded 16.8% ( 24051536 / 143466224 bytes) ...
Downloaded 19.8% ( 28360496 / 143466224 bytes) ...
Downloaded 22.6% ( 32456496 / 143466224 bytes) ...
Downloaded 24.8% ( 35553088 / 143466224 bytes) ...
Downloaded 27.9% ( 40074960 / 143466224 bytes) ...
Downloaded 30.2% ( 43302592 / 143466224 bytes) ...
Downloaded 33.0% ( 47333024 / 143466224 bytes) ...
Downloaded 35.3% ( 50691712 / 143466224 bytes) ...
Downloaded 37.4% ( 53608048 / 143466224 bytes) ...
Downloaded 40.1% ( 57474640 / 143466224 bytes) ...
Downloaded 42.5% ( 60915248 / 143466224 bytes) ...
Downloaded 45.3% ( 65060368 / 143466224 bytes) ...
Downloaded 47.4% ( 68025856 / 143466224 bytes) ...
Downloaded 49.9% ( 71597536 / 143466224 bytes) ...
Downloaded 52.5% ( 75365840 / 143466224 bytes) ...
Downloaded 55.3% ( 79298000 / 143466224 bytes) ...
Downloaded 58.6% ( 84098432 / 143466224 bytes) ...
Downloaded 61.3% ( 87981424 / 143466224 bytes) ...
Downloaded 64.0% ( 91880784 / 143466224 bytes) ...
Downloaded 66.3% ( 95092080 / 143466224 bytes) ...
Downloaded 68.3% ( 97975584 / 143466224 bytes) ...
Downloaded 70.9% (101678336 / 143466224 bytes) ...
Downloaded 73.4% (105282784 / 143466224 bytes) ...
Downloaded 75.3% (108100816 / 143466224 bytes) ...
Downloaded 78.0% (111934640 / 143466224 bytes) ...
Downloaded 80.5% (115440784 / 143466224 bytes) ...
Downloaded 83.5% (119848048 / 143466224 bytes) ...
Downloaded 85.8% (123124864 / 143466224 bytes) ...
Downloaded 87.7% (125844544 / 143466224 bytes) ...
Downloaded 90.0% (129072176 / 143466224 bytes) ...
Downloaded 92.7% (133020688 / 143466224 bytes) ...
Downloaded 95.3% (136707056 / 143466224 bytes) ...
Downloaded 97.1% (139312096 / 143466224 bytes) ...
Downloaded 99.4% (142556112 / 143466224 bytes) ...
Downloaded 100.0% (143466224 / 143466224 bytes)
Unpacking /Users/xxx/sdk/go1.18beta2/go1.18beta2.darwin-amd64.tar.gz ...
Success. You may now run 'go1.18beta2'下载完毕后，就可以使用go1.18beta2命令来测试和验证新版本的Go了。
$ go1.18beta2 version
go version go1.18beta2 darwin/amd64执行go1.18beta2 download之前，如果使用go1.18beta2 version命令会提示源码安装位置：
go1.18beta2: not downloaded. Run 'go1.18beta2 download' to install to /Users/xxx/sdk/go1.18beta2执行go1.18beta2 download之后，也提示了源码安装位置：
Unpacking /Users/xxx/sdk/go1.18beta2/go1.18beta2.darwin-amd64.tar.gz ...
Success. You may now run 'go1.18beta2'因此源码安装位置就在$HOME/sdk目录下。
执行go1.18beta2 env GOROOT也可以查看到源码地址：
$ go1.18beta2 env GOROOT
/Users/xxx/sdk/go1.18beta2默认情况下，使用go install装的不同版本Go的GOPATH默认路径都是同一个：$HOME/go，如下所示：
C02G21KCMD6M:go-tutorial$ go env GOPATH
/Users/xxx/go
C02G21KCMD6M:go-tutorial$ go1.18beta1 env GOPATH
/Users/xxx/go
C02G21KCMD6M:go-tutorial$ echo $HOME
/Users/xxx