Using head ala tail -f

Question

Log files that get extended at the tail can be read live using tail -f command

Is there anyway to do the same with a log that gets appended at the beginning?

The man page for head doesn't help.

Answer 1

TomH is correct, and also, how should head output the changes? However, if all you are looking for is a continually refreshed view of the first n lines, try

watch head file.txt

or

watch -n 1 -d head file.txt

Answer 2

Well you can't "append at the beginning" of a file. The only way to achieve that affect would be to rewrite the whole file, but short of doing a text match head would have no way of knowing what had happened.

It's easy for tail as it just keeps track of the position it read up to and then keeps trying to read more bytes beyond that position.