What's the best way to modify one line in a file?

[php_joe]

I want to write a snipit that will modify one line in a text file without changing any of the other lines.

 

I was thinking something like this:

<?
$newline = "new junk";
$linenumber = "3";
$file = "./textdocument.txt";
$line = file($file);
foreach($line as $key => $value){
if($key == $linenumber) $value = $newline;
}
$newcontent = implode("\n", $line);
$handle = fopen($file, "w");
fwrite($handle, $newcontent);
fclose($handle);
?>

 

Have I made a hash of this?

 

Is there a better way of doing it?

Maybe without exploding, looping, imploding, and rewriting all the lines?

 

Thanks in advance!

 

Joe

[trq]

If your on Linux the best way would probably be to use sed. What exactly do you need to modify?

[php_joe]

I'm using a Linux system, but I don't know 'sed'.

 

I just want to be able to modify a line on a text document without changing. nothing really fancy.

 

Something like this:

 

Cat
Dog
Bunny

 

and change it to:

 

Cat
Horse
Bunny

[trq]

<?php
  
  $file = "nameoffile.txt";
  if (exec("sed -i -e 's/Dog/Horse/' $file")) {
    echo "Horse replaced Dog";
  }

?>

[trq]

Oops... forgot. Bash will return 0 on success. I know it looks wrong but this will work.

 

<?php
  
  $file = "nameoffile.txt";
  $r = exec("sed -i -e 's/Dog/Horse/' $file");
  if ($r == 0) {
    echo "Horse replaced Dog";
  }

?>

[php_joe]

Correct me if I'm wrong, but that searches for a line based on the text in the line, right?

 

I want to single out a line by the line number and replace the text with the new text (the line # is the info I have, not the existing text).

 

This is what I've trimmed it down to so far:

<?
$line = file($textdocument);
$line[$line_number] = "$new_text\n";
$newcontent = implode("", $line);
$handle = fopen($worldlist, "w");
fwrite($handle, $newcontent);
fclose($handle);
?>

 

And it seems to work now.

[trq]

You could still use sed.

 

<?php

  exec("sed -i -e '" . $linenumber . "d' $textdocument");

?>

 

And I'm sticking to it.

[php_joe]

You could still use sed.

 

<?php

  exec("sed -i -e '" . $linenumber . "d' $textdocument");

?>

 

And I'm sticking to it.

 

Yes, that's what I was looking for.

 

Thank you very much!