To find out what packages are installed, you can run a list:
pear list-all
To update the PEAR repositories:
pear channel-update pear.php.net
To install a package, for instance, XML_RPC:
pear download XML_RPC
pear install XML_RPC
Note on installations: you don’t always have to download the module first, but, on dedicated server environments where /tmp is mounted noexec, you may need to download the module first and then move the archive into another directory and install it manually.
If you don’t know the specific name of a PEAR module you want to install, you can search for it:
pear search <name>
To show your PEAR configuration variables:
pear config-show
To change variables:
pear config-set variable_name <value>