Tried your code, there is one thing you may want to fix. I tried with this test file:

a
b
c
d
e
f
g
h
j
k
l

try to search for p, your snippet prints out lots of warning for using unitialized variable.

Tried to run without -w, so I can clearly see your debug info. It seems to me that your script didn't realize quickly enough that p actually does not exist.

I would like to borrow this snippet, be sure to post your new versions.