curl -O http://fhem.de/fhem-5.6.tar.gz 
 tar xf fhem-5.6.tar.gz 
 cd fhem-5.6 
 pacman -S make perl 
 make install 
 curl -O https://aur.archlinux.org/packages/fh/fhem/fhem.tar.gz 
 tar xf fhem.tar.gz 
 cp fhem/fhem.service /etc/systemd/system/ 
 sed -i 's/forking/oneshot\nRemainAfterExit=yes/' /etc/systemd/system/fhem.service 
 useradd fhem 
 chown -R fhem /opt/fhem 
 cd .. ; 
 rm -rf fhem-5.6 
 cd /opt/fhem/ 
 cp fhem.cfg fhem.cfg.org;
 mv fhem.cfg.demo fhem.cfg 
 systemctl start fhem 
 systemctl enable fhem

http://localhost:8083

update

fhem install archlinux