OK, it looks like you simply copied the import block from the first StackOverflow result for "golang read file" (the giveaway is that the order of imports is in the same non-formatted order as the top answer). That question, and its answer are covering more than simply reading in a file into a buffer.

The minimum is "os" and "io/ioutil"

    f, _ := os.Open("/etc/ttys")
    buff, _ := ioutil.ReadAll(f)

Edit: and as @exch pointed out, I forgot there's an ioutil.ReadFile helper too of you don't actually need access to the file object again.