Rudder

# service rudder-server-root restart
[...]
/etc/init.d/rudder-jetty: line 406: [: -lt: unary operator expected

The problem is that the script looks for java version:

JAVA_VERSION=$(${JAVA} -version 2>&1 | grep "java version" | sed 's%java version \"[0-9]\.\([0-9]\)\.[0-9].*\"%\1%')

whereas the result is:

# /bin/java -version
openjdk version "1.8.0_45" 
OpenJDK Runtime Environment (build 1.8.0_45-b13)
OpenJDK 64-Bit Server VM (build 25.45-b02, mixed mode)

The JAVA_VERSION is only here to check the version compatibility, and this error does not prevent the init script from running normally.