To mitigate the command injection vulnerability, here are some recommendations:
- Use input validation to ensure user-supplied data is sanitized and contains only expected values.
- Use parameterized queries to pass parameters to a query or command string in a secure manner.
- Design your app to run with the least privilege necessary to perform its intended functions.

Here's an example of a secure code that uses ProcessBuilder to execute commands safely:
```java
String[] cmd = {"ls", "-al", "/path/to/directory"};
ProcessBuilder pb = new ProcessBuilder(cmd);
Process p = pb.start();
```

```kotlin
val cmd = listOf("ls", "-al", "/path/to/directory")
val pb = ProcessBuilder(cmd)
val process = pb.start()
```
In this example, the ProcessBuilder class is used to create a secure command with the ls command, the -al flag, and the /path/to/directory parameter.

```dart
path = ProcessManager.instance.sanitizeInput(path);

// Split the input into words and sanitize each word
List<String> words = path.split(" ");
for (int i = 0; i < words.length; i++) {
words[i] = ProcessManager.instance.sanitizeInput(words[i]);
}

// Construct the command to list the files in the specified directory
List<String> cmd = ["ls"];
cmd.addAll(words);

// Execute the command using Process.run
ProcessResult result = await Process.run(
      cmd[0],
      cmd.sublist(1),
      includeParentEnvironment: false,
      environment: {});
```
In this example we accept the path from user somewhere,
First, we remove any special characters and prevent command injection. Then we split it into words and check each word again to prevent any malicious commands or arguments. Finally, we construct the 'ls' command using the sanitized input words.

```javascript
const { exec } = require('child_process');
const command = quote(["ls",arg1, arg1]);
 // Execute the external program and send the response back
execFile(command, args, (err, output) => {
      //...
});
```
In this example we are using shell-quote to parse and quote the shell command.


By implementing these recommendations, you can help protect your app from command injection attacks, ensuring the security and integrity of your application and its users.
