golang md5 file

md5.go

package main

import (
    "crypto/md5"
    "os"
    "io"
    "log"
    "encoding/hex"
)

func main() {
    h := md5.New()
    f, err := os.Open(os.Args[1])
    if err != nil {
        log.Fatal(err)
    }
    defer f.Close()
    if _, err := io.Copy(h, f); err != nil {
        log.Fatal(err)
    }
    os.Stdout.WriteString(hex.EncodeToString(h.Sum(nil)))
}

Another alternative is to use:

return fmt.Sprintf("%x", md5.Sum([]byte(text)))