PHP code that reads file content into a string and processes it

/*
*Read the file content into a string, while removing newlines and spaces at the beginning and end of the line.
*/
header("Content-type: text/html; charset=utf-8");
echo preg_replace('/((s)*(n)+(s)*)/i',',' ,file_get_contents('./file.php'));//End_php
//Output:
//aaaa,bbbb,cccc,dddd,eeee,ffff,gggg,hhhh,iiii, jjjj,kk kk,ll ll
?>

file.php content: aaaa

cccc dddd eeee ffff ggg hhhh iiii jjjj kkkk ll ll

//file.php replace space (x), Tab (T) effect aaaa

TTTT cccc ddddT xxxxxxxxxxxT eeeexxxxxxxxxx ffff ggg hhhhxxxxxxxxx xxxxxxxxxiii xxxxxxxxjjjjxxxxxxx kkxxxkkTT xxxxllxxllTT Txxxxxxxxxx TTTxx