PHP文件操作，跳过空行

I have a txt file generated by an instrument. The file needs some sanitation before the data is read into a mysql table. I have done this. But now due to some problem the data generated by the instruments contains empty lines in between and I want to remove it.

At present this is the code

 $target=$_FILES["report_file"]["tmp_name"];        
$file_contents = file_get_contents($target);
$file_contents = str_replace("?","",$file_contents);
$file_contents = str_replace(" ","",$file_contents);
$file_contents = str_replace("","",$file_contents);
$file_contents = str_replace("~","",$file_contents);
$file_contents = str_replace("","",$file_contents);
$file_contents = str_replace("#","",$file_contents);
$file_contents = str_replace(","," ",$file_contents);


file_put_contents($target,$file_contents);

$f = fopen($target, "r");

Can I use file_skip_empty_lines with file_put_contents? of how to put contents without empty lines?

You can trim empty lines using preg_replace

Trim whitespaces at the beginning of line

$file_contents = preg_replace("!^s+!m", "", $file_contents);

Remove empty lines

$file_contents = preg_replace("![
]+\s*[
]+!", "
", $file_contents);