How can I remove unwanted spaces from txt file - php

Question

I'm trying to modify my txt file what I'm using in dokuwiki.
I generate timestamp on top of the txt file like this:
function filecont($file,$data)
{
$fileContents = file($file);
array_shift($fileContents);
array_unshift($fileContents, $data);
$newContent = implode("\n", $fileContents);
$fp = fopen($file, "w+");
fputs($fp, $newContent);
fclose($fp);
}
And my original txt file looks like this:
Now when I use my function:
$txt= "Last generated: " . date("Y M D h:i:s");
filecont($file,$txt);
I get a result like this:
Now I don't want to remove my ====== Open IoT book ======, it's probably because I don't have empty space in the first line?
But the worst problem that I have Is that is generates many empty spaces what I don't want.
I only want to get last generated at the top of the txt file and anything else untouched

Answer 1

I tested your code and removed the extra newlines by changing the line:
$fileContents = file($file);
to
$fileContents = file($file, FILE_IGNORE_NEW_LINES);
Adding the FILE_IGNORE_NEW_LINES flag stops a newline being added to each element/line.
http://php.net/manual/en/function.file.php.
I also removed the array_unshift(), which leaves '====== Open IoT book ======' in the file.
So my final function looked like this:
function filecont($file,$data)
{
$fileContents = file($file, FILE_IGNORE_NEW_LINES);
//array_shift($fileContents); Removed to preserve '====== Open IoT book ======' line.
array_unshift($fileContents, $data);
$newContent = implode("\n", $fileContents);
$fp = fopen($file, "w+");
fclose($fp);
}

Answer 2

Might just delete this line
array_shift($fileContents);
solve your problem?

Answer 3

when you get elements of file you need to check whether Last generated: is as your first row or not accordong to it yu need to use array_shift
$fileContents = file($file);
if(stripos($fileContents[0],"Last generated:") !== false)
{
array_shift($fileContents); //if found use shift
}
array_unshift($fileContents, $data);