Cfrtjryk

I want to remotely log into a server and then find the pid of the specific port. After that kill that pid.

I tried this,

ssh -T test@192.168.94.139 ; "netstat -lnpt ; awk '$4 ~ /:2020$/ {sub(//.*/, "", $7); print $7}'" 

I should do this just only using netstat command

You miss the piping feature (| instead of ;) in your command. I propose this one:

ssh -t test@192.168.94.139  "sudo netstat -plnt | grep 2020 | awk '{print $7}' | sed s+/.*++g | sort -u | xargs kill"

I assume here you have sudo installed and permissions to use it on your server. My tests showed you may need it in order to get netstat to work properly with -p option.

I prefer here using grep+sed to avoid over-complicated (in my opinion) awk script.

• 
  -t : allows you to enter your user password to perform sudo command


• 
  grep 2020 : filters the port number


• 
  awk '{print $7}' : lets awk choose the right field


• 
  sed s+/.*++g : removes the / and following characters (note: the + sign replaces the traditional / here for shortness)


• 
  sort -u : just in case you would have several processes working with the port (happens if both IPv4 and IPv6 are used)


• 
  xargs kill : calls kill using the standard input as a parameter

You may need to add sudo to the last one, if the process to kill is owned by another user: sudo xargs kill

As an example, you could also use variables (note here the semi-colons used to separate commands without piping) :

server=test@192.168.94.139 ; port=2020 ; ssh -t $server "sudo netstat -plnt | grep $port | awk '{print $7}' | sed s+/.*++g | sort -u | xargs kill"

You got close enough to your goal. There are some missing points though.

1. No Semicolon after host IP required, the remote command should go right after the IP. So, remove the semicolon.


2. Replace the other semicolon in front of awk with a pipe sign | - that way the netstat output will go to the awk.


3. All the dollar sign needs to be escaped with a backslash. otherwise it is evaluated on the local machine

You will get the PID printed after above points done (if such is there). Then you will need to pass that PID to kill command. I'd suggest you use xargs kill as it looks the simplest here. PID will be accepted by kill command that way.

So the final version may look like:

ssh -T test@192.168.94.139 "netstat -lnpt | awk '$4 ~ /:2020$/ {sub(//.*/, "", $7); print $7}') | xargs kill"

Not the best look, but i suits your approach.