If you use Debian, to access the JerryWeb packages, add the following lines to your /etc/apt/sources.list file. 

# dev.jerryweb.org
deb http://dev.jerryweb.org/debian/ unstable main
deb-src http://dev.jerryweb.org/debian/ unstable main
The archive is signed using the JerryWeb archive key. To install this key on your system, type the following (as root): 
wget http://dev.jerryweb.org/packages/jerryweb-archive-key.asc
apt-key add jerryweb-archive-key.asc
apt-get update