On BSD sytems:cd /usr/ports/security/rkhunter; make install clean; rehash; rkhunter -c(or for help with rkhunter arguments do: rkhunter -h)On RedHat, Fedora, CentOS systems:yum -y install rkhunter; rkhunter -c(or for help with rkhunter arguments do: rkhunter -h)