// These variables hold the decoded operation specified by the first argument.
// op holds the operation we are doing (prtx).
// verbose tells whether the 'v' option was specified.
var (
	op      rune
	verbose bool
)

// setOp parses the operation string (first argument).
func setOp(arg string) {
	// Recognize 'go tool pack grc' because that was the
	// formerly canonical way to build a new archive