[RESOLVED] how to change certain lines in a file

[maciek4]

I have a file password.txt where I have two lines

user id
password

I want to open this file and change the second line of it. I only know how to open it and change the entire content but I dont know how to change only the second line.

$filename="files/password.txt";
$fp = fopen($filename, "w+") ;
fwrite($fp, $newpass);
fclose($fp); #close the file

I tried this but unsuccesfully

$lines=file('files/password.txt');
$fp = fopen($lines[1], "w+") ;
fwrite($fp, $newpass);
fclose($fp); #close the file

[mrmigu]

how about reading the contents of the file, opening it as an empty file, then writing the old login and the new password?

$lines=file('files/password.txt');
$fp = fopen('files/password.txt', "w") ;
fwrite($fp, $lines[0]);
fwrite($fp, $newpass);
fclose($fp); #close the file

[laserlight]

You can use [man]file/man to read the file as an array of lines, then modify the 2nd line, implode() the array and write back.

[maciek4]

worked. I did this:

$newpass = trim($_POST['newpass']);
$data = trim($lines[0]."".$newpass."\n"); 
    $fp = fopen($filename, "w+") ; 
fwrite($fp, $data);

fclose($fp);