Find which process is running on a certain port and kill it | Lavkush Blog

Find and Kill Processes Running on Specific Ports

In development, sometimes you need to free up a port being occupied by another process. This guide shows how to identify which process is running on a specific port and kill it using a combination of lsof and kill commands.

MacOS Only

Step 1: List All Processes Listening on Ports

To get a list of all processes that are currently listening on specific ports, use the following command:

$ sudo lsof -i -P | grep LISTEN

This command will show all processes that are listening on any port, with their associated PID (Process ID). The result should look something like this:

rapportd    123            lavkush    5u  IPv4 0x84512a8572c9xxxx      0t0    TCP *:62003 (LISTEN)
rapportd    123            lavkush    6u  IPv6 0x84512a857627xxxx      0t0    TCP *:62003 (LISTEN)
mongod      414            lavkush    9u  IPv4 0x84512a857926xxxx      0t0    TCP localhost:27017 (LISTEN)
Loom       3315            lavkush   28u  IPv4 0x84512a85785cxxxx      0t0    TCP localhost:11223 (LISTEN)
node      38238            lavkush   22u  IPv6 0x84512a857627xxxx      0t0    TCP *:5000 (LISTEN)
node      68336            lavkush   22u  IPv6 0x84512a858bb4xxxx      0t0    TCP *:443 (LISTEN)

Step 2: Identify the PID of the Process

In the output, the second column corresponds to the Process ID (PID) of the process running on the port. The last column shows the port number the process is using.

For instance, in the last line, the process node with PID 68336 is running on port 443.

Step 3: Kill the Process

Once you know the PID of the process, you can kill it using the kill command. The command to use is:

$ sudo kill -9 <PID>

For example, to kill the process running on port 443, the command would be:

$ sudo kill -9 68336

This will immediately stop the process.

Step 4: Verify That the Process Has Stopped

To confirm that the process has been successfully terminated, run the lsof command again to see if the process is still listening on the port:

$ sudo lsof -i -P | grep LISTEN

You should no longer see the process with PID 68336 in the output.

rapportd    123            lavkush    5u  IPv4 0x84512a8572c9xxxx      0t0    TCP *:62003 (LISTEN)
rapportd    123            lavkush    6u  IPv6 0x84512a857627xxxx      0t0    TCP *:62003 (LISTEN)
mongod      414            lavkush    9u  IPv4 0x84512a857926xxxx      0t0    TCP localhost:27017 (LISTEN)
Loom       3315            lavkush   28u  IPv4 0x84512a85785cxxxx      0t0    TCP localhost:11223 (LISTEN)
node      38238            lavkush   22u  IPv6 0x84512a857627xxxx      0t0    TCP *:5000 (LISTEN)

As you can see, the process that was running on port 443 is no longer there!

Additional Tips

Use ps for More Information: If you want more details about a process before killing it, you can use ps -p <PID> to get more information about the process, such as its command and owner.
Be Careful with kill -9: The -9 flag forces the process to terminate immediately. This might result in data loss if the process is performing important tasks. It’s often safer to try kill <PID> first, without -9.

By following these steps, you can quickly identify and kill processes occupying specific ports on your MacOS system, freeing up resources for other tasks.

Cheers