diff --git a/library/init/control/Alternative.lean b/library/init/control/alternative.lean
similarity index 100%
rename from library/init/control/Alternative.lean
rename to library/init/control/alternative.lean
diff --git a/library/init/control/Applicative.lean b/library/init/control/applicative.lean
similarity index 100%
rename from library/init/control/Applicative.lean
rename to library/init/control/applicative.lean
diff --git a/library/init/control/EState.lean b/library/init/control/estate.lean
similarity index 100%
rename from library/init/control/EState.lean
rename to library/init/control/estate.lean
diff --git a/library/init/control/Except.lean b/library/init/control/except.lean
similarity index 100%
rename from library/init/control/Except.lean
rename to library/init/control/except.lean
diff --git a/library/init/control/Functor.lean b/library/init/control/functor.lean
similarity index 100%
rename from library/init/control/Functor.lean
rename to library/init/control/functor.lean
diff --git a/library/init/control/Monad.lean b/library/init/control/monad.lean
similarity index 100%
rename from library/init/control/Monad.lean
rename to library/init/control/monad.lean
diff --git a/library/init/control/MonadFail.lean b/library/init/control/monadfail.lean
similarity index 100%
rename from library/init/control/MonadFail.lean
rename to library/init/control/monadfail.lean
diff --git a/library/init/control/Option.lean b/library/init/control/option.lean
similarity index 100%
rename from library/init/control/Option.lean
rename to library/init/control/option.lean
diff --git a/library/init/control/Reader.lean b/library/init/control/reader.lean
similarity index 100%
rename from library/init/control/Reader.lean
rename to library/init/control/reader.lean
diff --git a/library/init/control/State.lean b/library/init/control/state.lean
similarity index 100%
rename from library/init/control/State.lean
rename to library/init/control/state.lean
diff --git a/library/init/data/toString.lean b/library/init/data/tostring.lean
similarity index 100%
rename from library/init/data/toString.lean
rename to library/init/data/tostring.lean
diff --git a/library/init/IO.lean b/library/init/io.lean
similarity index 100%
rename from library/init/IO.lean
rename to library/init/io.lean
diff --git a/library/init/lean/compiler/constFolding.lean b/library/init/lean/compiler/constfolding.lean
similarity index 100%
rename from library/init/lean/compiler/constFolding.lean
rename to library/init/lean/compiler/constfolding.lean
diff --git a/library/init/lean/parser/stringLiteral.lean b/library/init/lean/parser/stringliteral.lean
similarity index 100%
rename from library/init/lean/parser/stringLiteral.lean
rename to library/init/lean/parser/stringliteral.lean