Linux shell to access tcp connection.

Open a new connection

1	exec FILE_DESCRIPTOR<>/dev/PROTOCOL/HOST/PORT

FILE_DESCRIPTOR: 0=stdin, 1=stdout, 2=stderr. So you can use numbers larger than 3.

PROTOCOL: tcp or udp

HOST: Host name or IP address.

PORT: Host listen port.

Send message

1	echo -e "MESSAGE" >&FILE_DESCRIPTOR

MESSAGE: The message which you want to send.

FILE_DESCRIPTOR: File descriptor when creating the connection..

Receive message

1	timeout SECOND cat <&FILE_DESCRIPTOR

SECOND: Wait SECOND seconds and then time out.

FILE_DESCRIPTOR: File descriptor when creating the connection..

Close connection

1	exec FILE_DESCRIPTOR<&-

FILE_DESCRIPTOR: File descriptor when creating the connection..

Example

1 2 3 4 5 6 7 8 9

exec 3<>/dev/tcp/192.168.5.250/1539 sleep 1 echo -e "test" >&3 timeout 5 cat <&3 sleep 1 echo -e "exit" >&3 timeout 5 cat <&3 sleep 1 exec 3<&-