how do i trim the blank line

[gca07738]

I have a file,how do i trim the blank line

111111111111111
22222222222

444444444444444

666666666666666666
77777777777

999999

[sfullman]

one way:
$file = file('myfile.php'); //one line per array entry
if(count($file)){
foreach($file as $v){
if(trim($v)){
$file2[]=$v
}
}
}
// ($file2 is your cleaned-up file, write it back or dow whatever)

antoerh way

$file = implode('', file('myfile.php'));
$newline = "\n";
$cr = "\r";
$fileSplit= preg_split("/($newline|$cr)+/",$file);
//re-implode
$file=implode("\n",$fileSplit);

Sam