在/ usr / local / go / src / strings中找到包字符串（build.go）和filedirs（reader.go）

I almost give up, just learned go and already having problems

these are lines that causes trouble

s := strings.ToUpper(tmp.String())
if _, err := io.Copy(f2, strings.NewReader(s)); err != nil {
    return err
}

I followed tutorial from packtub. please help me how to solve it. thanks

edit: this is what I put in .bash_profile

export GOPATH=$HOME/Projects/go
export PATH=$PATH:$GOPATH/bin
export GOROOT=/usr/local/go
export PATH=$PATH:$GOROOT/bin