Explain the difference between exec() vs system() vs passthru() ?

In PHP, the exec(), system(), and passthru() functions are used to execute external programs, but they handle the output differently:

1. exec():

   • Functionality: Executes the command and returns the last line of the output as a string.
   • Output Handling: Does not print the output directly; it can be captured and processed within the PHP script.
   • Return Value: Returns the last line of the command output or FALSE on error.
   • Example:
     php Copy

     $output = exec('ls -l');
     echo $output;

   • Use Case: Suitable when you need to capture and process the output programmatically.

2. system():

   • Functionality: Executes the command and prints the output directly to the output buffer.
   • Output Handling: Prints each line of the output as it is generated.
   • Return Value: Returns the last line of the command output as a string or FALSE on error.
   • Example:
     php Copy

     system('ls -l');

   • Use Case: Useful when you want to display the output directly to the user or the browser.

3. passthru():

   • Functionality: Executes the command and passes the raw output directly to the output buffer.
   • *Output Handling...