Useful links for common Ubuntu questions

Useful answers for common Ubuntu questions

There are quite a few questions that come up (at least for me) every time I install a new Ubuntu server. Unless you are a "Linux guy", you tend to forget how a specific task was done. Here are some of them:

Question:
When using a terminal window in a Linux graphical interface you may find out that the familiar "tab" used to auto-complete a command is now switching to the next open application, like in Windows. So, how to enable auto-complete in Ubuntu graphical interface terminal?

Answer:

Open Application Menu > Settings > Window Manager.
Click on Keyboard tab.
Clear the Switch window for same application setting.

Source: https://askubuntu.com/questions/545540/terminal-autocomplete-doesnt-work-properly/545578

Also, the Ctrl-Alt-D shortcut can be used to "show the desktop".

Question:
How do you verify and install the latest updates in Ubuntu?

Answer:
In a terminal enter the following command:

sudo apt update

This will update the various modules update locations. Then run:

 sudo apt upgrade

Confirm the installation of the updates (if any)


Question:
How can I tell what version of Ubuntu I'm running?

Answer:

 lsb_release -a 

or

 lsb_release -d

 Question:
How can I tell what process is listening to a port?

Answer:
Use the lsof command:

lsof -i :<port number>

 Example:

lsof -i :443

Add firewall rule:
sudo ufw allow port_number/transport_protocol

ex: sudo ufw allow 10050/tcp

Question:
What ports are in use?

Answer:
sudo lsof -i -P -n | grep LISTEN 



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