When I said read, I meant that the data read would be available to you to use in your script - /fseek does not make the read data available.
With your /fseek example there is no extra overhead with having to fopen() to NUL and fwrite() each line, then fclose(), like there is with /filter. Even though the results are discarded, mIRC will still wait for fwrite() to return a value before moving onto the next line.
And again - this is a very silly example, because there's little point in reading all of the data in a file but not doing anything with it.
Try coming up with practical examples and /filter will win nearly every time... like in my examples earlier in the thread
(reading the contents of a file into an @window)
You're right in saying that the biggest bottleneck is the interpreter, but that still means /filter is more efficient than the file handling command alternative.
