Package OS - Golang

create-directory.go

// Go Playground
// https://go.dev/play/p/MF-dT57HXTM

package main

import (
	"fmt"
	"os"
)

func main() {

	// creating dir /tmp/gopal
	if err := os.Mkdir("/tmp/gopal", 0750); err == nil {
		fmt.Println("Dir has been created.")
	} else {
		fmt.Println(err)
	}

	// create the dir with parent dir
	if err := os.MkdirAll("/tmp/go1/go2/go3", 0750); err == nil {
		fmt.Println("Dir has been created.")
	} else {
		fmt.Println(err)
	}
}

fetch-env-var.go

// Go Playground
// https://go.dev/play/p/9wqZwtlDdQk

package main

import (
	"fmt"
	"os"
)

func main() {

	// fetch Language env var
	// If env exists, return value else return empty
	fmt.Println("PAGER env:", os.Getenv("PAGER"))

	// to check if Env exists or not
	// if env var does not exists, retrun false else true
	if val, ok := os.LookupEnv("PAGER"); ok == false {
		fmt.Println("Env var does not exists.")
	} else {
		fmt.Println("Env val exists and value is:", val)
	}

}

fetch-file-stats.go

// Go Playground
// https://go.dev/play/p/Knvmf4bq5w0

package main

import (
	"fmt"
	"os"
)

func main() {

	fh, err := os.Stat("/etc/hosts")
	// Error check
	if err != nil {
		fmt.Println(err.Error())
	}

	// Fetching Stats

	fmt.Println("File Name:", fh.Name())
	fmt.Println("File Size (byte):", fh.Size())
	fmt.Println("File Permissions:", fh.Mode())
	fmt.Printf("File Permissions (octal): %#o\n", fh.Mode().Perm())
	fmt.Println("File, Is it a direcotory?:", fh.IsDir())
	fmt.Println("File, Is it a regular file?:", fh.Mode().IsRegular())
	fmt.Println("File last modification time:", fh.ModTime())
}

list-env-var.go

// Go Playground
// https://go.dev/play/p/rVolsli4vW8

package main

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

func main() {

	// fetch all the env variable
	env := os.Environ()

	// loop over env var
	for _, v := range env {

		// split the key and value
		data := strings.Split(v, "=")
		fmt.Println(data[0], "--->", data[1])
	}
}

read-file.go

// Go Playground
// https://go.dev/play/p/Q1aQHlJwwph

package main

import (
	"fmt"
	"os"
)

func main() {

	file, err := os.ReadFile("/etc/hosts")
	if err != nil {
		fmt.Println(err)
	} else {
		fmt.Println(string(file))
	}
}