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59 lines
1.2 KiB
Go
59 lines
1.2 KiB
Go
// Writing files in Go follows similar patterns to the
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// ones we saw earlier for reading.
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package main
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import (
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"bufio"
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"fmt"
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"io/ioutil"
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"os"
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)
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func check(e error) {
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if e != nil {
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panic(e)
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}
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}
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func main() {
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// To start, here's how to dump a string (or just
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// bytes) into a file.
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d1 := []byte("hello\ngo\n")
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err := ioutil.WriteFile("/tmp/dat1", d1, 0644)
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check(err)
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// For more granular writes, open a file for writing.
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f, err := os.Create("/tmp/dat2")
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check(err)
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// It's idiomatic to defer a `Close` immediately
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// after opening a file.
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defer f.Close()
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// You can `Write` byte slices as you'd expect.
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d2 := []byte{115, 111, 109, 101, 10}
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n2, err := f.Write(d2)
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check(err)
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fmt.Printf("wrote %d bytes\n", n2)
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// A `WriteString` is also available.
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n3, err := f.WriteString("writes\n")
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fmt.Printf("wrote %d bytes\n", n3)
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// Issue a `Sync` to flush writes to stable storage.
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f.Sync()
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// `bufio` provides buffered writers in addition
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// to the buffered readers we saw earlier.
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w := bufio.NewWriter(f)
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n4, err := w.WriteString("buffered\n")
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fmt.Printf("wrote %d bytes\n", n4)
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// Use `Flush` to ensure all buffered operations have
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// been applied to the underlying writer.
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w.Flush()
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}
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