diff --git a/lib/csys/csys.ex b/lib/core/core.ex
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rename to lib/core/core.ex
diff --git a/lib/csys/environ.ex b/lib/core/environ.ex
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diff --git a/lib/csys/program.ex b/lib/core/program.ex
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diff --git a/lib/shape/shape.ex b/lib/core/shape.ex
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diff --git a/lib/util.ex b/lib/core/util.ex
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rename to lib/core/util.ex