After running 
      ./configure , you will find
      the script 
      check_samhain.pl in the
      subdirectory 
      
      scripts/ of the samhain distribution, which you can
      copy to the 
      nagios 
      
      libexec/ directory. Before doing so, you may want
      to edit the script to set the correct path to the 
      
      libexec/ directory in the following line:
      use lib "/usr/local/nagios/libexec";
      The following recipe to use this script has been kindly provided by kiarna:
Nagios runs as user 'nagios'. However, in order to
      check the filesystem, you typically want to run 
      samhain as 'root'.
      You can use 
      sudo to fix this
      problem. In your 
      /etc/sudoers file, add
      the line:
	nagios ALL = NOPASSWD:/path/to/check_samhain
      Next, add the service to the nagios file 
      
      objects/commands.cfg:
	# 'check_samhain' command definition 
	define command{ 
	command_name check_samhain
	command_line /usr/bin/sudo -u root $USER1$/check_samhain -t 100 
      }Another option would be to install the check_samhain script with SUID permissions instead of using sudo (this requires that the suidperl package is installed and that samhain has been compiled with ./configure --enable-suid ...
	# 'check_samhain' command definition 
	define command{ 
	command_name check_samhain
	command_line $USER1$/check_samhain -t 100 
	}
      Checking the filesystem may take some time, so you may
      want to increase the nagios plugin timeout by changing the
      following line in 
      nagios.cfg from 60 to
      600:
      service_check_timeout=600Then add the service to the appropriate section in the
      nagios 
      service.cfg file.