Edit/delete a line in a file

[syndrome]

I want to open a file, go to a certain line in that file(line number x) and edit or delete that line with PHP.
I'm writing a news-administration-script with wich I want to be able to edit/delete a newsmessage stored in a line of my newsfile.
Thx for solution tips,

syndrome

 

[stakadush]

give each line a unique id and use that id to find a message.
for exmaple imagine having a title, author and text body (fields are seperated with a tab - \t)

ID\tTitle\tAuthor\tBody

1\tNews #1\tWebmaster\tToday....

better yet, use mysql