Display all the filesystem mount points and their respective type.

parsemounts.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

// Display all the mounted filesystems and their respective type.
// usage: go run parsemounts.go
//
// It parses the /proc/mounts file. Each line of the file is a white-space separated
// list of fields. The first field is the mount device, the second field is the mount point
// an the third field is the filesystem type, the other fields are mount options.
// If there's a whitespace or a backslash in one of the fields, it gets escaped. This program also unescapes them.
func main() {
	fsinfo := make(map[string]string)

	f, err := os.Open("/proc/mounts")
	if err != nil {
		panic(err)
	}
	defer f.Close()

	scanner := bufio.NewScanner(f)

	for scanner.Scan() {
		fields := strings.Fields(scanner.Text())
		mnt := unescape(fields[1])
		typ := unescape(fields[2])
		fsinfo[mnt] = typ
	}

	for k, v := range fsinfo {
		fmt.Printf("Mountpoint: %s\tType: %s\n", k, v)
	}

	if err := scanner.Err(); err != nil {
		panic(err)
	}
}

// unescape replaces the escape sequences that a string in /proc/mounts may have.
// It replaces octal whitespaces (\040, \011, \012) by their respective values,
// and after that, it replaces the escaped backslashes (\134).
func unescape(s string) string {
	s = strings.Replace(s, "\\040", " ", -1)
	s = strings.Replace(s, "\\011", "\t", -1)
	s = strings.Replace(s, "\\012", "\n", -1)
	s = strings.Replace(s, "\\134", "\\", -1)
	return s
}