How to execute an external command or program using syscall in Golang?

In Golang, you can execute an external command or program using the syscall package. Here's an example of how you can do it:

package main

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

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

	// Set command's stdout and stderr to current process's stdout and stderr
	// so that command's output will be printed to the console
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr

	// Run the command
	err := cmd.Run()
	if err != nil {
		// Handle error if any
		if exitError, ok := err.(*exec.ExitError); ok {
			// The command failed, exit status will be in exitError.ExitCode()
			fmt.Println("Command failed with exit status:", exitError.ExitCode())
		} else {
			// Some other error occurred
			fmt.Println("Command execution failed:", err)
		}
	}

	// Get the command's exit status
	if exitError, ok := err.(*exec.ExitError); ok {
		// Exit status will be in exitError.Sys().(syscall.WaitStatus)
		if status, ok := exitError.Sys().(syscall.WaitStatus); ok {
			fmt.Println("Exit status:", status.ExitStatus())
		}
	}
}

In this example, we use the exec.Command function to create a command object for the external command we want to execute. We set the command's Stdout and Stderr to the current process's Stdout and Stderr so that the command's output will be printed to the console. Then, we call the command's Run method to start the execution of the command.

If the command fails, the error returned by Run will be of type exec.ExitError, and you can get the exit status using exitError.ExitCode(). If the command succeeds, Run will return nil. You can also get the exit status using exitError.Sys().(syscall.WaitStatus), and then access the exit status using status.ExitStatus().

Note: The specific external command executed in this example is ls -l, which lists files and directories in the current directory on Unix-based systems. You can replace it with any other command you want to execute.