Golang os/exec: execute df command

main.go

package main

import (
	"fmt"
	"io"
	"os"
	"os/exec"
	"regexp"
	"strings"
	"encoding/json"
)

func main() {

	dfPath, err := exec.LookPath("df")
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	cmd := exec.Command(dfPath, "/")
	outPipe, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	err = cmd.Start()
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	b, err := io.ReadAll(outPipe)
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

	ss := strings.Split(string(b), "\n")

	if len(ss) >= 2 {
		headers := ss[0]
		values := ss[1]

		fmt.Println(headers)
		fmt.Println(values)

		headerSplitted, err := split(headers)
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		}

		valueSplitted, err := split(values)
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		}

		// the length of headerSplitted must be equal to valueSplitted
		headerSplitted = headerSplitted[:len(valueSplitted)]

		jsonMap := make(map[string]string)

		for i := 0; i < len(headerSplitted); i++ {
			jsonMap[headerSplitted[i]] = valueSplitted[i]
		}

		jsonBytes, err := json.Marshal(jsonMap)
		if err != nil {
			fmt.Println("error:", err)
		} else {
			fmt.Println(string(jsonBytes))
		}
	}

	err = cmd.Wait()
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}

}

// split function
func split(text string) ([]string, error) {
	re, err := regexp.Compile(`\s+|\s+$`)
	if err != nil {
		return nil, err
	}
	result := re.Split(text, -1)
	return result, nil
}

// output
// {"1K-blocks":"263174212","Available":"185765072","Filesystem":"/dev/sdd","Mounted":"/","Use%":"26%","Used":"63970984"}



// [Filesystem 512-blocks Used Available Capacity iused ifree %iused Mounted on /dev/disk3s1s1 1942700360 30677032 1352366864 3% 575614 4293938969 0% / ]
// [Filesystem 1K-blocks Used Available Use% Mounted on /dev/sdd 263174212 63969812 185766244 26% / ]