Posted by Philip Hallstrom on 04/06/05 20:23

> I need some help in searching string in a file.
>
> My requirement is to search the string,append something to the string .
> Write the string back to the file without changing other parts of the file.
>
> e.g
> Suppose I have the following string in a file
>
>
> Set-Cookie: T_COOKIE=127.0.0.1-saswat-9; path=/
>
>
> The fixed string is "Set-Cookie: T_COOKIE="and rest of the string is variable.
> I would like to change the string "127.0.0.1-saswat-9" to say
> "127.0.0.1-saswat-9-1234"
>
> My constraint is : I don't want to read the whole file into a buffer
> and work on that buffer as the file can be very large , sometimes more
> than 10 mb.
>
> My advantage is : I know that I will get the search string in first
> 200 bytes of the file , so I just need to read 200 bytes,play with
> that and write it back (overwriting the first 200 bytes with new 200
> some bytes) ..
>
> Would appreciate any help or pointers.

Something like this (completely un-checked)...

$fd = fopen("file", "r+");
$buf = fread($fd, 200);

// modify $buf...

fseek($fd, 0);
fwrite($fd, $buf, 200);

fclose($fd);

You might want to add some flock() stuff in there as well...

-philip

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