By using terminal commands, you can install software in Ubuntu from ‘official Ubuntu repository’ that is a part of Ubuntu apps. While installing you might encounter the following error: ‘Unable to locate package‘. This means software was not installed. You have to do the following to get rid of this error.
If you just installed Ubuntu, then you need to run upgrade and update commands in terminal.
sudo apt-get upgrade sudo apt-get update
Check spelling of the command statement. Syntax is the following:
sudo apt-get install <appname>
Command to install testdisk by using terminal:
sudo apt-get install testdisk
It command is correct, enable universe repository from Ubuntu software settings. Here is the error when I tried to install testdisk.
Enable Universe Repository for Software
Open ‘Software and Updates’ by typing ‘software’ in search.
Select Software and Updates.
Check the box that says, Community-maintained free and open-source software (universe).
Next time when you install apps from official Ubuntu repository, by using correct command and name of package, it will be installed in your computer.