diff --git a/src/examples/downloader.ml b/src/examples/downloader.ml
index 93638e5..a785549 100644
--- a/src/examples/downloader.ml
+++ b/src/examples/downloader.ml
@@ -1,5 +1,5 @@
 open! Base
-module Filename = Caml.Filename
+module Filename = Stdlib.Filename
 
 let downloader () =
   let open Genspio.EDSL in
@@ -154,7 +154,7 @@ let downloader () =
                    ; string " -> not HTTP(s) or FTP: NOT IMPLEMENTED" ] ] ) ] )
 
 let () =
-  match Caml.Sys.argv |> Array.to_list |> List.tl_exn with
+  match Stdlib.Sys.argv |> Array.to_list |> List.tl_exn with
   | ["make"; path] -> (
       let script = Genspio.Compile.to_many_lines (downloader ()) in
       let content =
@@ -163,12 +163,12 @@ let () =
       match path with
       | "-" -> Fmt.pr "\n`````\n%s`````\n%!" content
       | other ->
-          let o = Caml.open_out other in
-          Caml.Printf.fprintf o "%s%!" content ;
-          Caml.close_out o )
+          let o = Stdlib.open_out other in
+          Stdlib.Printf.fprintf o "%s%!" content ;
+          Stdlib.close_out o )
   | other ->
       Fmt.epr "Wrong command line: [%s]\n"
         (List.map ~f:(Fmt.str "%S") other |> String.concat ~sep:"; ") ;
       Fmt.epr "Usage:\n%s make <path>\n   Create the downloader script.\n%!"
-        Caml.Sys.argv.(0) ;
-      Caml.exit 1
+        Stdlib.Sys.argv.(0) ;
+      Stdlib.exit 1
diff --git a/src/examples/multigit.ml b/src/examples/multigit.ml
index e05885c..b0e5fd2 100644
--- a/src/examples/multigit.ml
+++ b/src/examples/multigit.ml
@@ -7,7 +7,7 @@
       $genspio_multigit $BINNPATH
 *)
 open! Base
-module Filename = Caml.Filename
+module Filename = Stdlib.Filename
 
 let ( // ) = Filename.concat
 let msg fmt = Fmt.kstr (Fmt.epr "%s\n%!") fmt
@@ -62,7 +62,7 @@ end
 
 let version_string =
   Fmt.str "%s (Genspio: %s)"
-    (try Caml.Sys.getenv "multigit_version" with _ -> "0")
+    (try Stdlib.Sys.getenv "multigit_version" with _ -> "0")
     Genspio.Meta.version
 
 module Multi_status = struct
@@ -504,7 +504,7 @@ end
 let cmdf fmt =
   Fmt.kstr
     (fun s ->
-      match Caml.Sys.command s with
+      match Stdlib.Sys.command s with
       | 0 -> ()
       | other -> Fmt.kstr failwith "CMD: %S failed with %d" s other )
     fmt
@@ -531,13 +531,13 @@ module Meta_repository = struct
   let cmd_to_string_list cmd =
     let i = Unix.open_process_in cmd in
     let rec loop acc =
-      try loop (Caml.input_line i :: acc)
-      with _ -> Caml.close_in i ; List.rev acc in
+      try loop (Stdlib.input_line i :: acc)
+      with _ -> Stdlib.close_in i ; List.rev acc in
     loop []
 
   let readme_md ~path:_ ~output =
-    let o = Caml.open_out output in
-    let open Caml.Format in
+    let o = Stdlib.open_out output in
+    let open Stdlib.Format in
     let fmt = formatter_of_out_channel o in
     let out f = fprintf fmt f in
     let sec c s = out "%s\n%s\n\n" s (String.make (String.length s) c) in
@@ -591,7 +591,7 @@ module Meta_repository = struct
     par "" ;
     section "Authors / Making-of" ;
     par
-      "This repository is generated by an OCaml program which itself was \
+      "This repository is generated by an OStdlib.program which itself was \
        written by [Seb Mondet](https://seb.mondet.org), it uses the \
        [Genspio](https://smondet.gitlab.io/genspio-doc/) EDSL library, and \
        serves as one of its examples of usage, see also its \
@@ -599,7 +599,7 @@ module Meta_repository = struct
     par
       "Similarly, you may check out the <https://github.com/smondet/cosc> \
        repository, which is also a bunch of shell scripts maintained by an \
-       OCaml program." ;
+       OStdlib.program." ;
     section "Example Session / Demo" ;
     let git_repos_top = "/tmp/git-repos-example" in
     let git_repos_hammerlab = git_repos_top // "hammerlab" in
@@ -724,21 +724,21 @@ end
 *)
 
 let () =
-  let path = Caml.Sys.argv.(1) in
+  let path = Stdlib.Sys.argv.(1) in
   cmdf "mkdir -p %s" (Filename.quote path) ;
   let repomode =
-    try String.(Caml.Sys.getenv "repomode" = "true") with _ -> false in
+    try String.(Stdlib.Sys.getenv "repomode" = "true") with _ -> false in
   let output filename script long_description =
     let gms = if repomode then path // "bin" // filename else path // filename in
     msg "Outputting %S" gms ;
     cmdf "mkdir -p %s" Filename.(quote (dirname gms)) ;
-    let o = Caml.open_out gms in
-    Caml.Format.(
+    let o = Stdlib.open_out gms in
+    Stdlib.Format.(
       fprintf
         (formatter_of_out_channel o)
         "#!/bin/sh\n\n%s\n\n%a\n"
         ( long_description ()
-          @ [ "The following is generated by an OCaml program using the \
+          @ [ "The following is generated by an OStdlib.program using the \
                Genspio EDSL."; "See <https://smondet.gitlab.io/genspio-doc/>."
             ]
         |> List.map ~f:(Fmt.str "# %s")
@@ -746,7 +746,7 @@ let () =
         Genspio.Compile.To_slow_flow.Script.pp_posix
         (Genspio.Compile.To_slow_flow.compile
            (script () |> Genspio.Transform.Constant_propagation.process) )) ;
-    Caml.close_out o ;
+    Stdlib.close_out o ;
     cmdf "chmod +x %s" (Filename.quote gms) in
   Multi_status.(output name script long_description) ;
   Activity_report.(output name script long_description) ;
diff --git a/src/examples/service_composer.ml b/src/examples/service_composer.ml
index ef3c69b..b52969f 100644
--- a/src/examples/service_composer.ml
+++ b/src/examples/service_composer.ml
@@ -36,7 +36,7 @@
   `cosc config show` is actually able to call `cosc-configuration-display`.
 *)
 open! Base
-module Filename = Caml.Filename
+module Filename = Stdlib.Filename
 
 let ( // ) = Filename.concat
 let msg fmt = Fmt.kstr (Fmt.epr "%s\n%!") fmt
@@ -46,7 +46,7 @@ module Gedsl = Genspio.EDSL
 let cmdf fmt =
   Fmt.kstr
     (fun s ->
-      match Caml.Sys.command s with
+      match Stdlib.Sys.command s with
       | 0 -> ()
       | other -> Fmt.kstr failwith "CMD: %S failed with %d" s other )
     fmt
@@ -87,24 +87,24 @@ module Script = struct
       output_path // String.concat ~sep:"-" (root :: t.relative_path)
     ```
 
-    The function `write` is the only real I/O of this whole OCaml program.
+    The function `write` is the only real I/O of this whole OStdlib.program.
   *)
   let write ?(compiler = `Slow_flow) t ~output_path ~root =
     let path = output_path // String.concat ~sep:"-" (root :: t.relative_path) in
-    let o = Caml.open_out path in
+    let o = Stdlib.open_out path in
     msg "Outputting “%s” to %s\n%!" t.description path ;
     ( match compiler with
     | `Slow_flow ->
         Fmt.(
           pf
-            (Caml.Format.formatter_of_out_channel o)
+            (Stdlib.Format.formatter_of_out_channel o)
             "#!/bin/sh\n\n%a\n" Genspio.Compile.To_slow_flow.Script.pp_posix
             (Genspio.Compile.To_slow_flow.compile
                (t.make ~root |> Genspio.Transform.Constant_propagation.process) ))
     | `Standard ->
-        Caml.Printf.fprintf o "#!/bin/sh\n\n%s\n"
+        Stdlib.Printf.fprintf o "#!/bin/sh\n\n%s\n"
           (Genspio.Compile.to_many_lines (t.make ~root)) ) ;
-    Caml.close_out o ; cmdf "chmod +x %s" path
+    Stdlib.close_out o ; cmdf "chmod +x %s" path
 end
 
 (*md Configuration of the scripts is bootstrapped with an environment
@@ -275,7 +275,7 @@ module Manual = struct
               (Environment.var_configuration_path env)
               env.Environment.default_configuration_path root root
           @ par
-              "The scripts are generated by an OCaml program which uses the \
+              "The scripts are generated by an OStdlib.program which uses the \
                [Genspio](https://smondet.gitlab.io/genspio-doc) EDSL/library. \
                The code generator serves as one of the usage examples of the \
                library, see its \
@@ -341,7 +341,7 @@ module Manual = struct
               let image = "smondet/genspio-doc-dockerfiles:apps406" in
               Fmt.kstr par
                 "If you have [`opam`](https://opam.ocaml.org), setting up the \
-                 genspio repository is easy (only simple, pure OCaml \
+                 genspio repository is easy (only simple, pure OStdlib.\
                  dependencies), if not, or if you just like Docker™, the \
                  generator is available in the `%s` image, see:"
                 image
@@ -912,7 +912,7 @@ module Example_script = struct
   let basic env root =
     let call s = Fmt.str "%s %s" root s in
     let conf = "/tmp/example-basic.d" in
-    let cmt fmt = Fmt.str Caml.("# " ^^ fmt) in
+    let cmt fmt = Fmt.str Stdlib.("# " ^^ fmt) in
     ( "basic"
     , [ cmt "We setup the configuration root path:"
       ; Fmt.str "export %s=%s" (Environment.var_configuration_path env) conf
@@ -1051,13 +1051,13 @@ let make ?default_configuration_path ?default_screen_name ~name ~output_path ()
 let () =
   let anon = ref [] in
   let anon_fun p = anon := p :: !anon in
-  let usage = Fmt.str "%s [-help] <path>" Caml.Sys.argv.(0) in
+  let usage = Fmt.str "%s [-help] <path>" Stdlib.Sys.argv.(0) in
   let name = ref None in
   let output_path = ref None in
   let config_path = ref None in
   let screen_name = ref None in
   let output_readme = ref false in
-  let module Arg = Caml.Arg in
+  let module Arg = Stdlib.Arg in
   let args =
     Arg.align
       [ ( "--name"
@@ -1077,7 +1077,7 @@ let () =
         , Fmt.str "<script-name> Where to write the scripts." ) ] in
   Arg.parse args anon_fun usage ;
   List.iter !anon ~f:(msg "Ignoring %s") ;
-  let die () = Caml.exit 2 in
+  let die () = Stdlib.exit 2 in
   let need opt = function
     | Some o -> o
     | None ->
diff --git a/src/examples/small.ml b/src/examples/small.ml
index f6e4504..8c776a6 100644
--- a/src/examples/small.ml
+++ b/src/examples/small.ml
@@ -1,10 +1,10 @@
 open! Base
 
-let examples = ref ([] : (Caml.out_channel -> unit) list)
+let examples = ref ([] : (Stdlib.out_channel -> unit) list)
 
 let example ?show name description code =
   let f o =
-    Caml.Printf.fprintf o
+    Stdlib.Printf.fprintf o
       "let () = examples := Example.make ~ocaml:%S %s %S %S %s :: !examples\n"
       code
       (match show with None -> "" | Some s -> Fmt.str "~show:%s" s)
@@ -303,7 +303,7 @@ Genspio.EDSL.(
 (******************************************************************************)
 
 let () =
-  let open Caml in
+  let open Stdlib.in
   let open Printf in
   let o = open_out Sys.argv.(1) in
   fprintf o "%s"
@@ -318,7 +318,7 @@ let examples = ref []
   fprintf o "%s"
     {ocaml|
 let () =
-    List.iter (List.rev !examples) ~f:(Example.run Caml.Format.std_formatter)
+    List.iter (List.rev !examples) ~f:(Example.run Stdlib.Format.std_formatter)
 |ocaml} ;
   close_out o ;
   printf "%s: Done.\n%!" Sys.argv.(0)
diff --git a/src/examples/vm_tester.ml b/src/examples/vm_tester.ml
index f8272b9..59c81e0 100644
--- a/src/examples/vm_tester.ml
+++ b/src/examples/vm_tester.ml
@@ -1,5 +1,5 @@
 open! Base
-module Filename = Caml.Filename
+module Filename = Stdlib.Filename
 
 let ( // ) = Filename.concat
 
@@ -18,7 +18,7 @@ module Shell_script = struct
     try String.sub ~pos:0 ~len:40 m with _ -> m
 
   let path {name; content; _} =
-    let open Caml in
+    let open Stdlib.in
     let hash = Marshal.to_string content [] |> Digest.string |> Digest.to_hex in
     let tag = String.sub hash 0 8 in
     "_scripts" // Fmt.str "%s_%s.sh" (sanitize_name name) tag
@@ -54,7 +54,7 @@ module Run_environment = struct
 
     let tmp_name_of_url = function
       | Http (url, ext) ->
-          ("_cache" // Caml.Digest.(string url |> to_hex))
+          ("_cache" // Stdlib.Digest.(string url |> to_hex))
           ^ Option.value_map ~default:"" ext ~f:(fun `Xz -> ".xz")
 
     let make_files files =
@@ -410,14 +410,14 @@ end
 let cmdf fmt =
   Fmt.kstr
     (fun cmd ->
-      match Caml.Sys.command cmd with
+      match Stdlib.Sys.command cmd with
       | 0 -> ()
       | other -> Fmt.kstr failwith "Command %S did not return 0: %d" cmd other
       )
     fmt
 
 let write_lines p l =
-  let open Caml in
+  let open Stdlib.in
   let o = open_out p in
   Base.List.iter l ~f:(Printf.fprintf o "%s\n") ;
   close_out o
@@ -427,7 +427,7 @@ let () =
     Fmt.kstr
       (fun s ->
         Fmt.epr "Wrong CLI: %s\n%!" s ;
-        Caml.exit 2 )
+        Stdlib.exit 2 )
       fmt in
   let example = ref None in
   let path = ref None in
@@ -458,7 +458,7 @@ let () =
               with
             | Some s -> s
             | None -> fail "Don't know VM %S" arg ) in
-  let module Arg = Caml.Arg in
+  let module Arg = Stdlib.Arg in
   let args =
     Arg.align
       [ ( "--ssh-port"
diff --git a/src/lib/EDSL.ml b/src/lib/EDSL.ml
index 9663489..9d31805 100644
--- a/src/lib/EDSL.ml
+++ b/src/lib/EDSL.ml
@@ -5,7 +5,7 @@ type c_string = Language.c_string
 type byte_array = Language.byte_array
 type fd_redirection = Language.fd_redirection
 
-let ( // ) = Caml.Filename.concat
+let ( // ) = Stdlib.Filename.concat
 
 open Language.Construct
 include Language.Construct.Base
@@ -109,7 +109,7 @@ let tmp_file ?tmp_dir name : file =
       [ get_tmp_dir; str "/"
       ; str
           (Fmt.str "genspio-tmp-file-%s-%s" clean
-             Caml.Digest.(string name |> to_hex) ) ] in
+             Stdlib.Digest.(string name |> to_hex) ) ] in
   let tmp = Str.concat_list [path; string "-tmp"] in
   object (_self)
     method get = get_stdout (call [string "cat"; path])
@@ -172,7 +172,7 @@ module Command_line = struct
     let variable {switches; _} =
       Fmt.str "%s_%s" prefix
         ( String.concat ~sep:"" switches
-        |> Caml.Digest.string |> Caml.Digest.to_hex ) in
+        |> Stdlib.Digest.string |> Stdlib.Digest.to_hex ) in
     let inits = ref [] in
     let to_init s = inits := s :: !inits in
     let cases = ref [] in
@@ -331,7 +331,7 @@ let fresh_name suf =
     object
       method v = 42
     end in
-  Fmt.str "g-%d-%d-%s" (Caml.Oo.id x) (Random.int 100_000) suf
+  Fmt.str "g-%d-%d-%s" (Stdlib.Oo.id x) (Random.int 100_000) suf
 
 let sanitize_name n =
   String.map n ~f:(function
diff --git a/src/lib/EDSL_v0.ml b/src/lib/EDSL_v0.ml
index 1ac12de..dd82023 100644
--- a/src/lib/EDSL_v0.ml
+++ b/src/lib/EDSL_v0.ml
@@ -5,7 +5,7 @@ type c_string = Language.c_string
 type byte_array = Language.byte_array
 type fd_redirection = Language.fd_redirection
 
-let ( // ) = Caml.Filename.concat
+let ( // ) = Stdlib.Filename.concat
 
 include Language.Construct
 
@@ -63,7 +63,7 @@ let tmp_file ?tmp_dir name : file =
       [ get_tmp_dir; c_string "/"
       ; c_string
           (Fmt.str "genspio-tmp-file-%s-%s" clean
-             Caml.Digest.(string name |> to_hex) ) ] in
+             Stdlib.Digest.(string name |> to_hex) ) ] in
   let tmp = C_string.concat_list [path; string "-tmp"] in
   object (self)
     method get = get_stdout (call [string "cat"; path])
@@ -127,7 +127,7 @@ module Command_line = struct
     let variable {switches; _} =
       Fmt.str "%s_%s" prefix
         ( String.concat ~sep:"" switches
-        |> Caml.Digest.string |> Caml.Digest.to_hex ) in
+        |> Stdlib.Digest.string |> Stdlib.Digest.to_hex ) in
     let inits = ref [] in
     let to_init s = inits := s :: !inits in
     let cases = ref [] in
@@ -139,7 +139,7 @@ module Command_line = struct
     let bool_of_var var = getenv (string var) |> Bool.of_string in
     let anon_tmp =
       Fmt.kstr tmp_file "parse-cli-%s"
-        Caml.(Marshal.to_string options [] |> Digest.string |> Digest.to_hex)
+        Stdlib.(Marshal.to_string options [] |> Digest.string |> Digest.to_hex)
     in
     let anon = anon_tmp#get |> Elist.deserialize_to_c_string_list in
     let applied_action =
@@ -293,7 +293,7 @@ let fresh_name suf =
     object
       method v = 42
     end in
-  Fmt.str "g-%d-%d-%s" (Caml.Oo.id x) (Random.int 100_000) suf
+  Fmt.str "g-%d-%d-%s" (Stdlib.Oo.id x) (Random.int 100_000) suf
 
 let sanitize_name n =
   String.map n ~f:(function
diff --git a/src/lib/common.ml b/src/lib/common.ml
index fe9cfee..d98d697 100644
--- a/src/lib/common.ml
+++ b/src/lib/common.ml
@@ -4,7 +4,7 @@ module Unique_name = struct
   let x = ref 0
 
   let create prefix =
-    Caml.incr x ;
+    Stdlib.incr x ;
     Fmt.str "%s_%d_%d" prefix !x (Random.int 100_000)
 
   let variable = create
diff --git a/src/lib/compile.ml b/src/lib/compile.ml
index 12cc836..d365e37 100644
--- a/src/lib/compile.ml
+++ b/src/lib/compile.ml
@@ -53,7 +53,7 @@ module To_posix = struct
                    (fun ppf s -> pf ppf "@[`%s`@]" s) )
                 more )
         ()
-      |> Caml.Filename.quote in
+      |> Stdlib.Filename.quote in
     str " printf -- '%%s\\n' %s >&2 " msg_str
 
   let one_liner =
@@ -116,7 +116,7 @@ let to_many_lines ?max_argument_length ?no_trap e =
   to_legacy `Multi_line ?max_argument_length ?no_trap e
 
 let quick_run_exn ?max_argument_length ?no_trap e =
-  match to_many_lines ?max_argument_length ?no_trap e |> Caml.Sys.command with
+  match to_many_lines ?max_argument_length ?no_trap e |> Stdlib.Sys.command with
   | 0 -> ()
   | other -> Fmt.failwith "Command returned %d" other
 
@@ -125,7 +125,7 @@ let to_string_hum e = Fmt.str "%a" pp_hum e
 
 let to_one_line_hum e =
   let buf = Buffer.create 42 in
-  let formatter = Caml.Format.formatter_of_buffer buf in
-  Caml.Format.pp_set_margin formatter 10_000_000 ;
-  Caml.Format.fprintf formatter "@[<h>%a@]@?" pp_hum e ;
+  let formatter = Stdlib.Format.formatter_of_buffer buf in
+  Stdlib.Format.pp_set_margin formatter 10_000_000 ;
+  Stdlib.Format.fprintf formatter "@[<h>%a@]@?" pp_hum e ;
   Buffer.contents buf
diff --git a/src/lib/language.ml b/src/lib/language.ml
index cf7b810..6f71027 100644
--- a/src/lib/language.ml
+++ b/src/lib/language.ml
@@ -1,7 +1,7 @@
 open Common
 
 (* Here we use the legacy module (too much code to change at once): *)
-module Format = Caml.Format
+module Format = Stdlib.Format
 
 type c_string = C_string
 type byte_array = Byte_Array
diff --git a/src/lib/standard_compiler.ml b/src/lib/standard_compiler.ml
index 7e639c6..bc8848b 100644
--- a/src/lib/standard_compiler.ml
+++ b/src/lib/standard_compiler.ml
@@ -147,7 +147,7 @@ let rec to_ir : type a. _ -> _ -> a Language.t -> internal_representation =
       match c_str with
       | Byte_array_to_c_string (Literal (Literal.String s))
         when Literal.Str.easy_to_escape s ->
-          argument (Caml.Filename.quote s |> check_length)
+          argument (Stdlib.Filename.quote s |> check_length)
       | Byte_array_to_c_string (Literal (Literal.String s))
         when Literal.Str.impossible_to_escape_for_variable s ->
           error ~comment_backtrace:comments (`Not_a_c_string s)
diff --git a/src/lib/to_slow_flow.ml b/src/lib/to_slow_flow.ml
index e1305ce..0f812aa 100644
--- a/src/lib/to_slow_flow.ml
+++ b/src/lib/to_slow_flow.ml
@@ -33,10 +33,10 @@ let expand_octal_command ~remove_l s =
 let m = ref 0
 
 let var_name ?expression ?script tag =
-  Caml.incr m ;
+  Stdlib.incr m ;
   let stag = String.map tag ~f:(function '-' -> '_' | a -> a) in
   Fmt.str "genspio_%s_%d_%d_%s" stag (Random.int 100_000_000) !m
-    Caml.(
+    Stdlib.(
       Marshal.to_string (expression, script) [Marshal.Closures]
       |> Digest.string |> Digest.to_hex)
 
@@ -49,7 +49,7 @@ module Tmp_db = struct
   let make ?(deletion_grouping = 20) how =
     let default_tmpdir =
       match how with
-      | `Fresh -> Caml.Filename.concat "/tmp" (var_name "tmpdir")
+      | `Fresh -> Stdlib.Filename.concat "/tmp" (var_name "tmpdir")
       | `Use p -> p in
     {default_tmpdir; tmp_file_db= []; deletion_grouping}
 
@@ -122,10 +122,10 @@ module Script = struct
         let v = Fmt.str "$(%s)" (expand_octal_command ~remove_l:false oct) in
         if not arithmetic then Fmt.str "\"%s\"" v else v
     | Literal_value s ->
-        let v = Caml.Filename.quote s in
+        let v = Stdlib.Filename.quote s in
         if arithmetic then Fmt.str "$(printf -- %s)" v else v
     | File s ->
-        let v = Fmt.str "$(cat %s)" (Caml.Filename.quote s) in
+        let v = Fmt.str "$(cat %s)" (Stdlib.Filename.quote s) in
         if not arithmetic then Fmt.str "\"%s\"" v else v
     | Tmp_file_in_variable s ->
         (* Parameters.(tmp_file_db := s :: !tmp_file_db) ; *)
@@ -150,7 +150,7 @@ module Script = struct
     | Literal_value s -> string_to_octal s
     | File f ->
         Fmt.str "$(cat %s | od -t o1 -An -v | tr -d ' \\n')"
-          (Caml.Filename.quote f)
+          (Stdlib.Filename.quote f)
     | Tmp_file_in_variable f ->
         (* Parameters.(tmp_file_db := f :: !tmp_file_db) ; *)
         Fmt.str "$(cat \"${%s}\" | od -t o1 -An -v | tr -d ' \\n')" f
@@ -162,7 +162,7 @@ module Script = struct
     | Unit -> assert false
     | Raw_inline s -> s
     | Literal_value _ -> assert false
-    | File f -> Caml.Filename.quote f
+    | File f -> Stdlib.Filename.quote f
     | Tmp_file_in_variable f ->
         (* Parameters.(tmp_file_db := f :: !tmp_file_db) ; *)
         Fmt.str "\"${%s}\"" f
@@ -343,7 +343,7 @@ let rec to_ir : type a. fail_commands:_ -> tmpdb:_ -> a t -> Script.t =
         let esc = string_to_octal v ~prefix:"\\" in
         mk (rawf "printf -- '%s' > %s" esc tmparg, tmp)
     | Literal_value v ->
-        mk (rawf "printf -- '%%s' %s > %s" (Caml.Filename.quote v) tmparg, tmp)
+        mk (rawf "printf -- '%%s' %s > %s" (Stdlib.Filename.quote v) tmparg, tmp)
     | File p -> mk (rawf ":", make [] (File p))
     | Tmp_file_in_variable p -> mk (rawf "cp \"${%s}\" %s" p tmparg, tmp)
     | Raw_inline s -> mk (rawf "printf -- '%%s' %s > %s" s tmparg, tmp)
@@ -725,7 +725,7 @@ let compile ?(default_tmpdir = `Fresh) ?(signal_name = "USR1")
   let fail_commands s =
     match trap with
     | `Exit_with _ ->
-        [ rawf "printf '%%s\\n' %s > %s " (Caml.Filename.quote s) tmparg
+        [ rawf "printf '%%s\\n' %s > %s " (Stdlib.Filename.quote s) tmparg
         ; rawf "kill -s %s ${%s}" signal_name pid ]
     | `None ->
         failwith "You cannot use the `fail` construct with no `trap` strategy"
@@ -851,9 +851,9 @@ let test () =
       let ir = compile expr in
       fprintf std_formatter "==== TEST %d ====\n%a\n%!" idx Script.pp_posix ir ;
       let script_file = Fmt.str "/tmp/script-%d.sh" idx in
-      let o = Caml.open_out script_file in
+      let o = Stdlib.open_out script_file in
       fprintf (formatter_of_out_channel o) "\n%a\n%!" Script.pp_posix ir ;
-      Caml.flush o ;
-      Caml.close_out o ;
-      let res = Fmt.kstr Caml.Sys.command "sh %s" script_file in
+      Stdlib.flush o ;
+      Stdlib.close_out o ;
+      let res = Fmt.kstr Stdlib.Sys.command "sh %s" script_file in
       fprintf std_formatter "\nRESULT: %d\n" res )
diff --git a/src/lib/transform.ml b/src/lib/transform.ml
index a1f16a3..78bb202 100644
--- a/src/lib/transform.ml
+++ b/src/lib/transform.ml
@@ -370,7 +370,7 @@ module Constant_propagation = struct
     let count = ref 0 in
     let check ?trace name e res =
       let p = process ?trace e in
-      Caml.incr count ;
+      Stdlib.incr count ;
       match Poly.(p = res) with
       | true -> ()
       | false ->
diff --git a/src/test-lib/test_lib.ml b/src/test-lib/test_lib.ml
index eba7adf..ecf765d 100644
--- a/src/test-lib/test_lib.ml
+++ b/src/test-lib/test_lib.ml
@@ -1,9 +1,9 @@
 open! Base
 
-let ( // ) = Caml.Filename.concat
+let ( // ) = Stdlib.Filename.concat
 
-module Filename = Caml.Filename
-module Sys = Caml.Sys
+module Filename = Stdlib.Filename
+module Sys = Stdlib.Sys
 
 module Test = struct
   type t =
@@ -82,7 +82,7 @@ module Shell_directory = struct
            if String.length long > 30 then String.sub long ~pos:0 ~len:30
            else long )
           (List.length args) returns
-          Caml.(
+          Stdlib.(
             Marshal.to_string script [Marshal.Closures]
             |> Digest.string |> Digest.to_hex
             |> fun s -> String.sub s 0 10)
@@ -358,9 +358,9 @@ module Example = struct
         ( match Genspio.Compile.To_posix.(string ~options:multi_line) code with
         | Ok script ->
             let tmp = Filename.temp_file "genspio-example" ".sh" in
-            let o = Caml.open_out tmp in
-            Caml.Printf.fprintf o "\n%s\n" script ;
-            Caml.close_out o ;
+            let o = Stdlib.open_out tmp in
+            Stdlib.Printf.fprintf o "\n%s\n" script ;
+            Stdlib.close_out o ;
             (* ff fmt "@[<hov 2>* Compiled:@ `%s`@ (%d bytes)@]@\n" tmp (String.length script); *)
             let out = Filename.temp_file "genspio-example" ".out" in
             let err = Filename.temp_file "genspio-example" ".err" in
@@ -371,10 +371,10 @@ module Example = struct
             let show_file name path =
               let fence = String.make 50 '`' in
               ff fmt "@\n%s:@\n@\n%s@\n" name fence ;
-              let i = Caml.open_in path in
+              let i = Stdlib.open_in path in
               let rec loop () =
                 try
-                  ff fmt "%c" @@ Caml.input_char i ;
+                  ff fmt "%c" @@ Stdlib.input_char i ;
                   loop ()
                 with _ -> () in
               loop () ; ff fmt "@\n%s@\n@\n" fence in
diff --git a/src/test/main.ml b/src/test/main.ml
index 3374bdf..44d4e3f 100644
--- a/src/test/main.ml
+++ b/src/test/main.ml
@@ -1,5 +1,5 @@
 open! Base
-module Filename = Caml.Filename
+module Filename = Stdlib.Filename
 open Tests.Test_lib
 module Compile = Genspio.Language
 module Construct = Genspio.EDSL_v0
@@ -635,7 +635,7 @@ let () =
   @@ exits ~name:"getenv" 25
        (let open Construct in
        let alternate_get_env v =
-         (* We cannot use OCaml's Sys.getenv because the compilation output may
+         (* We cannot use OStdlib.s Sys.getenv because the compilation output may
             be run on a different host/system (through SSH or alike). *)
          exec ["sh"; "-c"; Fmt.str "echo ${%s} | tr -d '\\n'" v]
          |> get_stdout |> Byte_array.to_c in
@@ -1224,14 +1224,14 @@ let () =
     Fmt.kstr
       (fun s ->
         Fmt.epr "Error: %s\nUsage: %s\n%!" s usage ;
-        Caml.exit 1 )
+        Stdlib.exit 1 )
       fmt in
   let anon_fun p = anon := p :: !anon in
   let no_compilation_tests = ref false in
   let extra_slow_flow_tests = ref false in
   let extra_transform_cp_tests = ref false in
   let filter_tests = ref None in
-  let module Arg = Caml.Arg in
+  let module Arg = Stdlib.Arg in
   let args =
     Arg.align
       [ ( "--important-shells"
@@ -1294,13 +1294,13 @@ let () =
       let todo = Test_directory.contents testdir ~path testlist in
       List.iter todo ~f:(function
         | `File (p, v) ->
-            let mo = Caml.open_out p in
-            Caml.Printf.fprintf mo "%s\n" v ;
-            Caml.close_out mo
+            let mo = Stdlib.open_out p in
+            Stdlib.Printf.fprintf mo "%s\n" v ;
+            Stdlib.close_out mo
         | `Directory v -> Fmt.kstr Sys.command "mkdir -p '%s'" v |> ignore ) ) ;
   let errors =
     if !no_compilation_tests then false else compilation_error_tests () in
   if !extra_slow_flow_tests then Genspio.To_slow_flow.test () ;
   if !extra_transform_cp_tests then
     Genspio.Transform.Constant_propagation.test () ;
-  Caml.exit (if errors then 23 else 0)
+  Stdlib.exit (if errors then 23 else 0)