jekyll 2.2.0 | Error: Address already in use - bind(2) - jekyll

Question

I am new to Jekyll blogging and trying to view blog locally on
http://localhost:4000
but failed.
➜ my-awesome-site > jekyll serve
Notice: for 10x faster LSI support, please install http://rb-gsl.rubyforge.org/
Configuration file: /home/Git/my-awesome-site/_config.yml
Source: /home/Git/my-awesome-site
Destination: /home/Git/my-awesome-site/_site
Generating...
done.
Configuration file: /home/Git/my-awesome-site/_config.yml
jekyll 2.2.0 | Error: Address already in use - bind(2)
I tried
$ lsof -wni tcp:3000
$ lsof -wni tcp:4000
but both of them return nothing.
My Ruby version is:
➜ my-awesome-site > ruby --version
ruby 2.0.0p451 (2014-02-24 revision 45167) [universal.x86_64-darwin13]
What should I do next? I've re-installed jekyll already but the same problem remains.

Answer 1

See the comments in http://jekyllrb.com/docs/usage/, should help you:
If you need to kill the server, you can kill -9 1234 where "1234" is
the PID.
If you cannot find the PID, then do, ps aux | grep jekyll
and kill the instance. Read more.

Answer 2

Steps here fixed it for me. I had to append 'sudo' along with the commands.
$> sudo lsof -wni tcp:4000
It will give you information of process running on tcp port 4000 which also contains PID (Process ID). Now use command below to kill the process.
$> sudo kill -9 PID
Now you can execute jekyll serve command to start your site

Answer 3

Try to see which process is using that port, kill it and run again or try running jekyll on different port.

Answer 4

If #Matifou's answer here doesn't work, do the following instead:
The fix for anyone: run jekyll serve on an unused port:
Two ways:
In your _config.yml file, specify a port other than 4000 like this, for example:
port: 4001
OR (my preferred choice), add --port 4001 to your jekyll serve command, like this, for example:
bundle exec jekyll serve --livereload --port 4001
From: https://jekyllrb.com/docs/configuration/options/#serve-command-options
See my answer here: Is it possible to serve multiple Jekyll sites locally?
My particular problem: NoMachine is interfering:
When I run:
bundle exec jekyll serve --livereload --drafts --unpublished
I get these errors:
jekyll 3.9.0 | Error: Address already in use - bind(2) for 127.0.0.1:4000
.
.
.
/usr/lib/ruby/2.7.0/socket.rb:201:in `bind': Address already in use - bind(2) for 127.0.0.1:4000 (Errno::EADDRINUSE)
ps aux | grep jekyll doesn't show any processes running except this grep command itself. So, that doesn't help.
sudo lsof -wni tcp:4000, however, shows a running nxd nx daemon process:
$ sudo lsof -wni tcp:4000
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
nxd 914803 nx 3u IPv4 7606783 0t0 TCP *:4000 (LISTEN)
nxd 914803 nx 4u IPv6 7599664 0t0 TCP *:4000 (LISTEN)
I discovered this is due to my NoMachine remote login server.
If running NoMachine, click on the NoMachine icon in the top-right of your task bar. Ex: this is on Ubuntu 20.04:
Then click on "Show server status" --> Ports, and you'll see that NoMachine is running nx on Port 4000, which is interfering:
So, use the fix above to serve jekyll on a different port, such as 4001 instead of 4000. I recommend leaving the NoMachine port settings as-is, on port 4000, because NoMachine says:
Automatic updates require that hosts with NoMachine client or server installed have access to the NoMachine update server on port 4000 and use the TCP protocol.
See also:
Is it possible to serve multiple Jekyll sites locally?
my answer