I took the steps at A new, community-hosted Unreal Engine Wiki - Announcements - Epic Developer Community Forums needed to update and recompile an already-installed Unreal Engine and put it in a handy bash script.
UNREAL_DIR="/opt/UnrealEngine" # must be owned by you (don't use sudo)
set -e
cd "$UNREAL_DIR"
git pull https://github.com/EpicGames/UnrealEngine.git release # must have linked your github account to your epic account.
./Setup.sh
./GenerateProjectFiles.sh
if "$1" == "-clean" ] ;then
make CrashReportClient-Linux-Shipping \
ShaderCompileWorker \
UnrealPak \
UnrealLightmass \
UnrealFrontend \
UE4Editor \
ARGS=-clean
fi
make