Catching panics in Golang

Question

With the following code, if no file argument is given, a panic is thrown for line 9 panic: runtime error: index out of range as expected.

How can I \'catch\

Answer 1

Go is not python, you should properly check for args before you use it:

func main() {
    if len(os.Args) != 2 {
         fmt.Printf("usage: %s [filename]\n", os.Args[0])
         os.Exit(1)
    }
    file, err := os.Open(os.Args[1])
    if err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s", file)
}