#First Go software:
echo $GOPATH #to see if it’s set or empty
export GOPATH=$HOME/Web/Go/src/github.com/username/helloUsingLibrary
echo $GOPATH # to see it has changed
mkdir -p $GOPATH/src/hello
cd !$ # cd ~/Web/Go/src/github.com/username/helloUsingLibrary/src/hello
echo $PATH
export PATH=$PATH:$GOPATH/bin
echo $PATH # to see it has changed
vim hello.go # You can create hello.go
mkdir $GOPATH/stringutil #in that folder, create reverse.go
go build $GOPATH/stringutil #Or, in the package's source directory, just:go build (This won't produce an output file. To do that, you must use go install, which places the package object inside the pkg directory of the workspace.)
Whenever the go tool installs a package or binary, it also installs whatever dependencies it has. So when you install the hello program, the stringutil package will be installed as well, automatically.
go install hello.go
$GOPATH/bin/hello # to run hello.go or « hello » because $GOPATH/bin is now in the PATH