I installed PHPUnit using the PEAR installer a few days ago (I also installed Selenium RC for testing in PHP purpose). Now I want to uninstall it (also delete all related folders and files)
I ran the following command:
pear uninstall phpunit/PHPUnit
and the console displayed:
phpunit/PHPUnit not installed
I checked the PHPUnit folder, it was still there?
Was it uninstalled? I try to reinstall a new PHPUnit, but the console displayed:
No releases available for package "pear.phpunit.de/PHPUnit"
How can I reinstall it?
Here’s the output of pear list -c pear.phpunit.de:

Here’s output of pear list -c pear.phpunit.de:

That might be because of sub-components (Extensions, Framework). However you must not be concerned about that.
To install the latest version, do the following two commands:
This will take some time, and will update all that is currently installed. As you have some extensions already available and the latest version of PHPUnit might require those, so update them to prevent failure in the next command:
This should now install it:
Troubleshooting PEAR
As you reported in comments, this did not work out. Probably pear is in a state that it does not know where top and bottom is. Time to force. First, clear the cache:
Then force channel updates:
Then force the phpunit install: