useful for applications that need to run scripts as root
(default ubuntu)
/usr/bin/pkexec --disable-internal-agent /bin/echo 'foo'
(kde)
/usr/bin/kdesudo --comment 'System needs administrative privileges. Please enter your password.' /bin/echo 'foo'
(gksu)
/usr/bin/gksudo --preserve-env --sudo-mode --description 'System' /bin/echo 'foo'