<?php
    $filename = 'example.txt';
    if (! ($fp = fopen($filename, 'r') ) ) {
    echo 'Unable to open file '. $filename;
    }else {
    $file_size = filesize($filename);
    if (  !($contents = fread($fp, $file_size)  ) ) {
    echo 'Error: read operation failed';
    }else{
    echo 'content read is ' . $contents;
    }
    fclose($fp);
    }
   ?>

<?php
    $content =  'This content is to test';
    if ( is_writable ('example.txt') ){
    $fp = fopen ('example.txt', 'w');
    if (  !$fp ){
    echo 'error : coud not open file  example.txt  ';
    }else{
    if (! ( $length  =  fwrite($fp, $content )  )   ){
    echo 'writing to the file failed';
    }else{
    echo 'Content wrote  successfully to the file';
    }
   fclose($fp);
   }
   }
  ?>