What Process Is Hogging My Port On Mac Os

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Address already in use

Damn. Did I leave a server running somewhere? Sometimes you’re not sure where you left a server running, or where something is running you never knew about. I’m finally writing this down, as I always have to look it up. I found this solution in a StackOverflow post.

Here’s how to get all of the processes by what port they’re using.

sudo lsof -iTCP -sTCP:LISTEN -n -P

As A Shell Function

Looking at it, I realized I would never remember it, given how infrequently I need it. So, I wrote a function. You should be able to pop this into your .bashrc or .zshrc, or whatever you’re using.

function whats_using {
  if [ -z $1 ]; then
    sudo lsof -iTCP -sTCP:LISTEN -n -P
    sudo lsof -iTCP -sTCP:LISTEN -n -P | grep $1

Now you can search for what’s using a port like so, or don’t specify a port number to return all results.

➜  whats_using 8181
com.docke  4082 cory   20u  IPv4 0xa05b24c922aef1a1      0t0  TCP *:8181 (LISTEN)
com.docke  4082 cory   21u  IPv6 0xa05b24c91a710329      0t0  TCP [::1]:8181 (LISTEN)