command.go
func (c *Command) Arg(v interface{}) *Command {
	c.args = append(c.args, fmt.Sprintf("%v", v))
	return c
}
func (c *Command) Arg(v interface{}) *Command {
	c.args = append(c.args, fmt.Sprintf("%v", v))
	return c
}
func ( c * Command ) Arg ( v interface { } ) * Command { c . args = append ( c . args , fmt . Sprintf ( " " , v ) ) return c }
// Arg appends a new argument to the command.
Arg appends a new argument to the command .