I'm trying to open a port on remote system using ssh & netcat like this:  ssh user@host.tld 'netcat -l 7777 &'but it waits to show output and doesn't go to background!I tried nohup before netcat but got same result;  How can I run netcat in background using ssh on remote system? 
How send a command to background using ssh on remote system
ssh;background process;netcat
You can use this:ssh -f user@host.tld sh -c 'netcat -l 7777 > /dev/null 2>&1 &'Check this thread.