37: sha2sum

This exercise is pending. Quick notes about this exercise:

• My implemention is at https://lcthw.dev/go/go-coreutils
• https://www.gnu.org/software/coreutils/manual/html_node/sha2-utilities.html
• sha512 -- https://pkg.go.dev/crypto/sha512@go1.25.3

The Code

View Source file go-coreutils/sha512sum/main.go Only

package main

import (
    "fmt"
    "flag"
    "os"
    "log"
    "crypto/sha512"
)

type Opts struct {
    Inputs []string
}

func parse_opts() Opts {
    var opts Opts

    flag.Parse()
    opts.Inputs = flag.Args()

    return opts
}

func to_hex(hash [sha512.Size]byte) string {
    result := ""

    for _, b := range hash {
        result += fmt.Sprintf("%x", b)
    }

    return result
}

func main() {
    opts := parse_opts()

    for _, fname := range opts.Inputs {
        in_data, err := os.ReadFile(fname)
        if err != nil { log.Fatal(err) }

        hash := sha512.Sum512(in_data)

        fmt.Println(to_hex(hash), fname)
    }
}