I have a server with an open port which receives between 50 and 1000 messages per second. By message I mean that a single line of text is sent.

Essentially we want to record these messages in a file which will be processed every hour (or x minutes).

I have created a bash script (see below) which runs in the background and it works except when I kill the socat process (so I can take the file for processing and it can start a new file) we get part of a message, plus I am sure we are losing messages during the split second that socat is down. 

```
DELAY="3600"
while true
do  
    NEXT_STOP=`date +%s --date "$DELAY second"`
    (
        while [ "$(date +%s)" -lt "$NEXT_STOP" ]
        do
            killall socat
            socat -u TCP-LISTEN:6116,reuseaddr,keepalive,rcvbuf=131071,reuseaddr OPEN:/var/ais/out_v4.txt,creat,append
        done
    ) & sleep $DELAY ; killall socat

    mv /var/ais/out_v4.txt "/var/ais/_socat_received/"$(date +"%Y-%m-%d-%T")"__out_v4.txt"
done

```

Is there a way to:

1. Get socat to rotate its output file without killing the process
2. Or can we purge the content of the file whilst SOCAT is writing to it. e.g. cut the first 10000 lines into another file, so the output file remains a manageable size?

Many thanks in advance