Is it possible to run Drush without root? I run a Linux server that is administered by a friend of mine, and at the moment I work with Filezilla.

I've heard that Drush is a trivial installation: it seems to require no configuration and work out of the box. 

However, it looks for configuration in several places:


  Drush installation directory,  the home directory (as .drushrc.php), 
  root directory of a Drupal installation, and  site directory of a
  Drupal installation.  Since the configuration files are just PHP
  scripts, they can  contain any PHP code that you would like to have
  executed on startup of Drush.  one could for instance call ini_set()
  to set the value of a PHP configuration option.


and the configuration file /opt/drush/drushrc.php with following content:



# Allow Drush to use 128 MB of memory. Use -1 for no limit. ini_set('memory_limit', '128M');


I see this is necessary because PHP's default is too low, but I'm not sure if I need higher-level privileges because of it.

Do I have to have root-level permissions on the server, or am I able to work with Drush without them? 

Update:  As far as i understand this, i only have to ask my admin to get some more privileges (permissions)Note according to BetaRides answer i need to have more than only the access-data that the FileZilla needs - that are provided for the filezilla! Guess so - but i don not need root-permissions.

btw - i have secure-shell-access (ssh2 access) guess that this is enough -With that i can setup a sftp-connection to the server with filezilla just lemme know - if i can use the exactly same data for the shell access (with the command line tool=?!=
You do not need root-level permissions to use Drush: it'll work as long as the user invoking it has direct access to the Drupal installation directory.

Having the the same filesystem permissions as the web user should be enough for most operations: but for things like downloading modules, you'll need write-level access to the Drupal directory as well.