netcat

ncat on MacOS

first download nmap for Mac. Then run a UDP server: ncat -lu -p 9999

send/receive messages

server:

nc -lu -p 9999

client:

nc -u 192.168.0.101 9999  # type lines terminal

upload file with curl to netcat server

nc -l localhost 8000
curl -F "text=default" -F "file1=@a.html" -F "file1=@a.txt" localhost:8000

to receive data from Globe4D driver

nc -lu -p 12345

netcat for windows

part of nmap project (nmap.org). Same syntax: ncat -lu 192.168.2.123 8888

read line from netcat

while:
do
  echo listening...

  nc 10.0.0.134 8081 | while read line
  do

    if [ ! -f /root/bel.txt ]
    then
      echo $line > /root/bel.txt
    fi

    grep -q bel.txt -e $line
    if [ $? -eq 0 ]; then
      echo "gevonden: $line"
    fi

    #echo test:$line
  done
done

tips

quit netcat client after receiving certain string

nc localhost 9000 | grep -q "Hoi" (somehow the word 'Hoi' needs to be followed by two linebreaks)

in a while loop:

while :
do
  echo listening...
  nc localhost 9000 | grep -q "Hoi"
  echo Bel AAN
  sleep 1
  echo Bel UIT
done

listen to port

nc -lu -p 7777
nc -lu 192.168.2.123 8888

send UDP

echo "hello" > /dev/udp/10.87.24.174/8888
ls > /dev/udp/10.87.24.174/8888