Clone the repository (it needs to be connected through git to work properly) into some location, preferably straight into the home directory ($HOME or ~) and make sure the folder is called karhu (lowercase). Then make sure the correct environment variables are set for everything to work. On UNIX you can put this in ~/.bash_profile:

#!

export KARHU_HOME=$HOME/karhu
export PATH=$PATH:$KARHU_HOME/tools/<mac|linux>

Replace <mac|linux> with mac in macOS and linux on Linux. $KARHU_HOME is used for lots of things, and adding the path to the tools directory enables tools such as karhubuild and karhuproj.

On Mac, the path to libclang's dynamic library needs to be made visible:

#!
export DYLD_FALLBACK_LIBRARY_PATH=$DYLD_FALLBACK_LIBRARY_PATH:/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib