Sometimes you want to start a Horde installation from scratch because something went wrong during installation. If you did not install into a separate PEAR directory, of if that separate installation went wrong, you cannot simply remove one folder to have all Horde components installed. The files from the PEAR packages might be installed at several places, depending in your PEAR configuration.
As long as your PEAR installation is still functional and still lists all Horde PEAR packages (check with pear list -c horde), you can use the following command to uninstall all Horde PEAR packages at once:
pear uninstall `pear list -c horde | tail -n +4 | awk '{ print "horde/"$1 }'`
If you installed into a separate PEAR directory, make sure to use the correct pear command and flags again, e.g.:
/var/www/horde/pear/pear -c /var/www/horde/pear.conf uninstall \
`/var/www/horde/pear/pear -c /var/www/horde/pear.conf list -c horde |tail -n +4|awk '{ print "horde/"$1 }'`