sudo apt install rkhunter         # On Debian, Ubuntu and Mint.
sudo yum install rkhunter         # On RHEL/CentOS/Fedora/Rocky/AlmaLinux.
sudo emerge -a sys-apps/rkhunter  # On Gentoo Linux.
sudo apk add rkhunter             # On Alpine Linux.
sudo pacman -S rkhunter           # On Arch Linux.
sudo zypper install rkhunter      # On OpenSUSE.