Replace a particular line in a text file using php?

Question

I have a text file that stores lastname, first name, address, state, etc as a string with a | delimiter and each record on a separate line.

I have the part where I need to store each record on a new line and its working fine; however, now I need to be able to go back and update the name or address on a particular line and I can't get it to work.

This how to replace a particular line in a text file using php? helped me here but I am not quite there yet. This overwrites the whole file and I lose the records. Any help is appreciated!

After some edit seems to be working now. I am debugging to see if any errors.

$string= implode('|',$contact);   

$reading = fopen('contacts.txt', 'r');
$writing = fopen('contacts.tmp', 'w');

$replaced = false;

while (!feof($reading)) {
 $line = fgets($reading);

  if(stripos($line, $lname) !== FALSE)  {           
if(stripos($line, $fname) !== FALSE) {  
    $line = "$string";
    $replaced = true;
}       
   }

  fwrite($writing, "$line");
  //fputs($writing, $line);
 }
fclose($reading); fclose($writing);

// might as well not overwrite the file if we didn't replace anything
if ($replaced) 
{
  rename('contacts.tmp', 'contacts.txt');
} else {
 unlink('contacts.tmp');
}   

Answer 1

It seems that you have a file in csv-format. PHP can handle this with fgetcsv() http://php.net/manual/de/function.fgetcsv.php

if (($handle = fopen("contacts.txt", "r")) !== FALSE) {
    $data = fgetcsv($handle, 1000, '|')
    /* manipulate $data array here */
}

fclose($handle);

So you get an array that you can manipulate. After this you can save the file with fputcsv http://www.php.net/manual/de/function.fputcsv.php

$fp = fopen('contacts.tmp', 'w');

foreach ($data as $fields) {
    fputcsv($fp, $fields);
}

fclose($fp);

Well, after the comment by Asad, there is another simple answer. Just open the file in Append-mode http://de3.php.net/manual/en/function.fopen.php :

$writing = fopen('contacts.tmp', 'a');