# Start netcat listening on an ephemeral port (0 means kernel picks port)
# It will wait for a connection, then write that data to output_file
-
- nc -l 0 > output_file &
+ # -d is needed or else it will give up too early.
+ nc -d -l 0 > output_file &
# pid of the nc running in the background
NCPID=$!
