[SOLVED] How to eat away a file?

[resnow]

I have a chunk of truly random data in a text file. I'd like my script to take the first two bytes of the data, store it, and then delete it from the file. This way the file would serve as a constant supply of fresh randomness.

 

The reading part is easy, thanks to "fread", but I couldn't figure out how to delete just the first two bytes from the file.

 

Help would be very much appreciated!

[trq]

You will need to read the entire file into a string, take what you want using substr, then write the rest back using substr and fread.

[lemmin]

Just overwrite everything with the first two characters missing. I think it would be like this:

$buffer = file_get_contents("file.txt");
file_put_contents("file.txt", substr_replace($buffer, substr($buffer, 2), 0);

[resnow]

Thanks guys! The script is now able to take what it needs from the file, and save the rest for later use. 

 

Problem solved.

[kenrbnsn]

If you're going to have many instances of the script running in parallel (i.e. it's web based), you may want to look at the flock() to ensure that only one instance of the script is reading/writing the file at a time.

 

Ken