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I am trying to kill a process in the command line for a specific port in ubuntu.

If I run this command I get the port:

sudo lsof -t -i:9001

so...now I want to run:

sudo kill 'sudo lsof -t -i:9001'

I get this error message:

ERROR: garbage process ID "lsof -t -i:9001".
Usage:
  kill pid ...              Send SIGTERM to every process listed.
  kill signal pid ...       Send a signal to every process listed.
  kill -s signal pid ...    Send a signal to every process listed.
  kill -l                   List all signal names.
  kill -L                   List all signal names in a nice table.
  kill -l signal            Convert between signal numbers and names.

I tried sudo kill 'lsof -t -i:9001' as well

Answers

You want to use backtick, not regular tick:

sudo kill -9 `sudo lsof -t -i:9001`

If that doesn't work, you could also use $() for command interpolation:

sudo kill -9 $(sudo lsof -t -i:9001)