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Dockerfile-ubuntu1804

@@ -19,11 +19,11 @@ RUN apt-get update && \
 #  more recent versions of boost that the system CMake doesn't now about.
 RUN wget https://github.com/Kitware/CMake/releases/download/v3.16.2/cmake-3.16.2.tar.gz && \
     tar -zxf cmake-3.16.2.tar.gz && \
-    pushd cmake-3.16.2 && \
+    cd cmake-3.16.2 && \
     ./bootstrap && \
     make -j $(nproc) && \
     make install && \
-    popd && \
+    cd .. && \
     rm -rf cmake-3.16.2 && \
     rm -rf cmake-3.16.2.tar.gz