cd

# Examine the environment

echo $G4COMP
ls $G4COMP/

echo $G4INSTALL

env  | grep G4

# work with a copy of example B1 

mkdir g4work
cd g4work

echo $G4COMP
ls $G4COMP/

mkdir taskA
cd taskA

cp -r $G4INSTALL/share/Geant4-10.4.2/examples/basic/B1  ./

cp -r $G4EXAMPLES/basic/B1   ./

ls 
less README
less exampleB1.cc

mkdir build
cd build
cmake -DGeant4_DIR=$G4COMP/  ../
make

./exampleB1