<?php

    // the file, that should be modified
    $file = 'testfile.txt';
    $length = 20;
   
    // function getContent
    function getContent( $file, $length )
    {
        if ( !file_exists( $file ) )
            return false;
           
        if ( !is_readable( $file ) )
            return false;
           
        if ( !$handle = fopen( $file, "r") )
        {
            echo "Opening $file failed.";
            return false;
        }
       
        if ( !$content = fread( $handle, $length ) )
        {
            echo "Reading content of $file failed.";
            return false;
        }
       
        fclose( $handle );
       
        return $content;
    }
   
    // function setContent
    function setContent( $file, $code )
    {
        if ( !file_exists( $file ) )
            return false;

        if ( !is_writable( $file ) )
            return false;

        if ( !$handle = fopen( $file, "w") )
        {
            echo "Opening $file failed.";
            return false;
        }

        if ( !fwrite( $handle, stripslashes($code)) )
        {
            echo "Writing content to $file failed.";
            return false;
        }

        fclose( $handle );
    }
   
    # END OF FUNCTIONS ...

    $content = getContent( $file, $length );

    if( trim($content) == '' )
    {
        $content = 0;
    }
   
    echo 'Inhalt der Textdatei: ' . $content  . '
';
   
    setContent( $file, ++$content );
   
    echo 'reload';

?>