Go Academy · Lesson

Writing Files and Temp Files

WriteFile, OpenFile flags, and temp files

os.WriteFile

os.WriteFile writes a byte slice to a file atomically (truncate then write). Simple for small files.

err := os.WriteFile("output.txt", []byte("hello"), 0644)
if err != nil { log.Fatal(err) }

os.Create creates or truncates a file and returns an *os.File. Always close with defer.

f, err := os.Create("output.txt")
if err != nil { return err }
defer f.Close()
f.WriteString("hello\n")