`os.Open(name)` opens the named file for reading and returns an `*os.File`.

• Read file contents.
• Work with file handles for streaming reads.

f, err := os.Open("data.txt")
if err != nil {
    return err
}
defer f.Close()
 
b, err := io.ReadAll(f)
if err != nil {
    return err
}
_ = b

• Always `defer f.Close()` to release resources.
• For read+write or create, use `os.OpenFile` with flags.
• For small files, `os.ReadFile` is a convenient helper.

• os.ReadFile
• os.OpenFile
• os.Create

• handle /ˈhændl/: tay cầm file (descriptor)
• streaming /ˈstriːmɪŋ/: đọc theo luồng (từng phần)
• release /rɪˈliːs/: giải phóng
• flag /flæɡ/: cờ tuỳ chọn