[svnpenn]

Well I understand that part but I was temporarily confused on how to kill the rtmpdump I start afterwards with the output.

Cygwin has long known issues with non-Cygwin binaries, AKA RtmpDump. If you want to kill RtmpDump with Cygwin, you need to do one of these

# Instead of invoking like this
rtmpdump -o a.flv -r rtmp://server.com/app/playpath
# Invoke like this, then hit Ctrl+C to stop
timeout 1d rtmpdump -o a.flv -r rtmp://server.com/app/playpath

# Set RtmpDump to simply stop after certain time
rtmpdump -o a.flv -r rtmp://server.com/app/playpath -B 10

# Invoke RtmpDump under cmd.exe instead of Bash
rtmpdump -o a.flv -r rtmp://server.com/app/playpath

# Compile RtmpDump as a Cygwin binary instead of Native Windows binary
rtmpdump -o a.flv -r rtmp://server.com/app/playpath

# Kill RtmpDump using Cygwin commands
ps -W | awk /rtmpdump/'{print$4;exit}' | xargs kill -f

# Use Windows Task Manager to kill
rtmpdump.exe