string replace in a large file with php

Question

I am trying to do a string replace for entire file in PHP. My file is over 100MB so I have to go line by line and can not use file_get_contents(). Is there a

Answer 1

something like this?

$infile="file";
$outfile="temp";
$f = fopen($infile,"r");
$o = fopen($outfile,"a");
$pattern="pattern";
$replace="replace";
if($f){
     while( !feof($f) ){
        $line = fgets($f,4096);
        if ( strpos($pattern,"$line") !==FALSE ){
            $line=str_replace($pattern,$replace,$line);
        }
        fwrite($o,$line);
     }
}
fclose($f);
fclose($o);
rename($outfile,$infile);