Module Topkg.OS.File

module File: sig .. end

File operations.


Famous file paths

val null : Topkg.fpath

null represents a file on the OS that discards all writes and returns end of file on reads.

val dash : Topkg.fpath

dash is "-". This value is is used by Topkg.OS.File.read and Topkg.OS.File.write to respectively denote stdin and stdout.

Existence and deletion

val exists : Topkg.fpath -> bool Topkg.result

exists file is true if file is a regular in the file system and false otherwise. Symbolic links are followed.

val must_exist : Topkg.fpath -> Topkg.fpath Topkg.result

must_exist file is file if file is a regular file in the file system and an error otherwise. Symbolic links are followed.

val delete : ?must_exist:bool -> Topkg.fpath -> unit Topkg.result

delete ~must_exist file deletes file file. If must_exist is true (defaults to false) an error is returned if file doesn't exist.

Folding over file hierarchies

val fold : ?skip:(Topkg.fpath -> bool) ->
(Topkg.fpath -> 'a -> 'a) -> 'a -> Topkg.fpath list -> 'a Topkg.result

fold_files skip f acc paths folds f over the files found in the file hierarchies starting at paths. Files and directories p for which skip p is true are skipped. skip defaults to (fun _ -> false).

Reading and writing

val read : Topkg.fpath -> string Topkg.result

read file is file's contents. If file is Topkg.OS.File.dash reads from stdin and the channel is not closed when the function returns.

val write : Topkg.fpath -> string -> unit Topkg.result

write file content writes content to file. If file is Topkg.OS.File.dash writes to stdout and flushes but doesn't close the channel when the function returns.

val write_subst : Topkg.fpath -> (string * string) list -> string -> unit Topkg.result

write_subst file vars content is like Topkg.OS.File.write except any occurence of a string of the form "%%ID%%" in content is replaced by the value of List.assoc "ID" vars, if any.

Temporary files

val tmp : unit -> Topkg.fpath Topkg.result

tmp () creates a temporary file and returns its name. The file is destroyed at the end of program execution.