package main import ( "fmt" "log" "os" ) // GetFileSize returns file size or error if e.g. file doesn't exist func GetFileSize(path string) (int64, error) { st, err := os.Lstat(path) if err != nil { return -1, err } return st.Size(), nil } func main() { path := "main.go" size, err := GetFileSize(path) if err != nil { log.Fatalf("GetFileSize failed with '%s'\n", err) } fmt.Printf("File %s is %d bytes in size\n", path, size) }