How to execute external shell commands or processes using the os package in Golang?

To execute external shell commands or processes using the os package in Golang, you can use the os/exec package. Here's an example:

package main

import (
	"fmt"
	"log"
	"os"
	"os/exec"
)

func main() {
	// Command to execute
	cmd := exec.Command("ls", "-l")

	// Set the command's output to os.Stdout
	cmd.Stdout = os.Stdout

	// Execute the command
	err := cmd.Run()
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println("Command executed successfully")
}

In this example, we execute the ls -l command by creating an exec.Cmd struct and setting its Stdout field to os.Stdout to redirect the command's output to the standard output. The cmd.Run() function is used to execute the command.

If you want to capture the command's output, you can use the CombinedOutput() function instead of Run(). Here's an example:

package main

import (
	"fmt"
	"log"
	"os"
	"os/exec"
)

func main() {
	// Command to execute
	cmd := exec.Command("ls", "-l")

	// Execute the command and capture its output
	output, err := cmd.CombinedOutput()
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(string(output))
	fmt.Println("Command executed successfully")
}

In this example, the CombinedOutput() function is used to execute the command and capture its output. The output is stored in the output variable, which can be converted to a string and printed.