为什么在运行`go get golang.org / x / tools / cmd / godoc`时没有创建二进制文件？

Question

godoc and gotour can be built and run from their respecitve source directory with go build. What is the reason a gotour binary created when one go get it and that is not the case for godoc.

Command Line Output:

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> ls

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> go env
GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/user/.gvm/pkgsets/go1.5.1/global"
GORACE=""
GOROOT="/home/user/.gvm/gos/go1.5.1"
GOTOOLDIR="/home/user/.gvm/gos/go1.5.1/pkg/tool/linux_amd64"
GO15VENDOREXPERIMENT=""
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> go get golang.org/x/tools/cmd/godoc

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> ls
pkg  src

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> go get golang.org/x/tour/gotour

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> ls 
bin  pkg  src

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> ls bin/
gotour

[ user@pc:~/.gvm/pkgsets/go1.5.1/global ]
>> cd src/golang.org/x/tools/cmd/godoc/

[ user@pc:~/.gvm/pkgsets/go1.5.1/global/src/golang.org/x/tools/cmd/godoc ]
>> go build

[ user@pc:~/.gvm/pkgsets/go1.5.1/global/src/golang.org/x/tools/cmd/godoc ]
>> ./godoc 
usage: godoc package [name ...]
    godoc -http=:6060
  -analysis string
        comma-separated list of analyses to perform (supported: type, pointer). See http://golang.org/lib/godoc/analysis/help.html
  -ex
        show examples in command line mode
  -goroot string
        Go root directory (default "/home/user/.gvm/gos/go1.5.1")
  -html
        print HTML in command-line mode
  -http string
        HTTP service address (e.g., ':6060')
  -httptest.serve string
        if non-empty, httptest.NewServer serves on this address and blocks
  -index
....

Answer 1

Godoc is special as it is an official tool being part of the Go distribution.

So if you go get godoc, the result binary will not be placed under $GOPATH/bin where all other executables go, but under $GOROOT/bin.

Gotour is not special in this way, so it gets installed into your $GOPATH/bin.