The docs say nothing about what build vs install does

My expectation was that it's like make install; i.e. it takes the compiled stuff and puts in its final location (/usr/local/bin/my_new_toy or whatever) but it seems that it puts things in GOROOT/bin

Can I tell go to do a make install - i.e. put things elsewhere? Or do I just write a makefile (please tell me no)?

If you want binary files to go to a specific location, you can use the environment variable GOBIN :

The bin/ directory holds compiled commands. Each command is named for its source directory, but only the final element, not the entire path. That is, the command with source in DIR/src/foo/quux is installed into DIR/bin/quux, not DIR/bin/foo/quux. The foo/ is stripped so that you can add DIR/bin to your PATH to get at the installed commands. If the GOBIN environment variable is set, commands are installed to the directory it names instead of DIR/bin.

Source : http://golang.org/cmd/go/#hdr-GOPATH_environment_variable

GOBIN=/usr/local/bin/ go install

If you want per-project bin/ directory then you can simply append your project path to GOPATH, however you must have your code under $project-path/src/ and go install will put all the binaries in $project-path/bin.

export GOPATH=/dir1:/dir2:/dir3

If GOBIN is not set, binaries from /dir1/src end up in /dir1/bin, binaries from /dir2/src end up in /dir2/bin, and so on (and binaries from $GOROOT/src end up in $GOROOT/bin).

Source : https://groups.google.com/forum/#!topic/golang-nuts/-mN8R_Fx-7M

And you can also just use (thanks JimB):

go build -o /path/binary-name

go build vs go install:

go build just compile the executable file and move it to the destination. go install do a little more. It moves the executable file to $GOPATH/bin and cache all non-main packages which imported to $GOPATH/pkg. The cache will be used in the next compile if it not changed yet.

A package tree after go build and go install:

.
├── bin
│   └── hello  # by go install
└── src 
    └── hello
        ├── hello  # by go build
        └── hello.go

More complete reference.