~snip~
Can you add and post the system information of your device?
If it is running the latest version of ubuntu or older version?
Since the ranochigo suggested above works to you and you've got Bitcoin Core version v0.18.1.0 then try this
sudo apt-get dist-upgrade
If not then do this next step.
Currently, the latest version of Ubuntu is "Ubuntu 20.10 (Groovy Gorilla)"
Try this(This method is for an old version of Ubuntu but it might work also on the latest version)
- Copy this
deb http://ppa.launchpad.net/luke-jr/bitcoincore/ubuntu groovy main
deb-src http://ppa.launchpad.net/luke-jr/bitcoincore/ubuntu groovy main
Step 4: Open a terminal and type:
sudo gedit /etc/apt/sources.list
This will open a text editor containing the list of archives that your system is currently using. Scroll to the bottom of the file and paste the lines you copied in the step above.
Save the file and exit the text editor.
Step 5: Then copy this
E76343E19921CAF7F6FA2B9F480495056EC244E1
Step 6: Now you need to add that key to your system so Ubuntu can verify the packages from the PPA. In your terminal, enter:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E76343E19921CAF7F6FA2B9F480495056EC244E1
Replace E76343E19921CAF7F6FA2B9F480495056EC244E1 with whatever you copied in the step 5.
This will now pull down the PPA's key and add it to your system.
Important: This is not an endorsement of any of the software in PPAs. You must make sure you trust the PPA owner before installing their software.
Step 7: Now, as a one-off, you should tell your system to pull down the latest list of software from each archive it knows about, including the PPA you just added:
sudo apt-get update
Now you're ready to start installing software from the PPA! If you already have the software installed and you're adding the PPA to get a more recent/different version, you may just need to run:
sudo apt-get dist-upgrade
Just edited some steps above and got the source from here
https://help.launchpad.net/Packaging/PPA/InstallingSoftwareAnd the source.list entries from luke-jr under "Technical details about this PPA" here
https://launchpad.net/~luke-jr/+archive/ubuntu/bitcoincoreIf it doesn't work and you are using a lower version than "Ubuntu 20.10 (Groovy Gorilla)" try to choose other entries under "Technical details about this PPA" Then repeat the procedure above or you might need to update your Ubuntu to the latest version.