batteries
  1. Overview
  2. Docs
Legend:
Library
Module
Module type
Parameter
Class
Class type

File manipulation.

  • author David Teller
Utilities
val lines_of : string -> string BatEnum.t

lines_of name reads the contents of file name as an enumeration of lines. The file is automatically closed once the last line has been reached or the enumeration is garbage-collected.

val count_lines : string -> int

count_lines filename count the number of lines in given file. Lines are read by the stdlib's input_line function.

  • since 3.1.0
val write_lines : string -> string BatEnum.t -> unit

write_lines name lines writes strings given by lines to file name with newline character appended to each line.

val size_of : string -> int

size_of name returns the size of file name in bytes.

val size_of_big : string -> Int64.t

size_of_big name returns the size of file name in bytes, as a 64-bit integer.

This function is provided as the size of a file larger than 1 Gb cannot be represented with an int on a 32-bit machine.

File permissions

File permissions are used when creating a file to allow controlling which users may read, write or open that file. To use a permission, create a value of type permission and pass it as argument to open_in, open_out, with_file_in or with_file_out.

type permission

The list of operations which are permitted on a file.

val default_permission : permission

Default permissions.

val user_read : permission

Give the current user permission to read the file. Ignored under Windows.

val user_write : permission

Give the current user permission to write the file

val user_exec : permission

Give the current user permission to execute the file. Ignored under Windows.

val group_read : permission

Give the permission to read the file to the group containing the user. Ignored under Windows.

val group_write : permission

Give the permission to write the file to the group containing the user. Ignored under Windows.

val group_exec : permission

Give the permission to execute the file to the group containing the user. Ignored under Windows.

val other_read : permission

Give the permission to read the file to the rest of the world. Ignored under Windows.

val other_write : permission

Give the permission to modify the file to the rest of the world. Ignored under Windows.

val other_exec : permission

Give the permission to execute the file to the rest of the world. Ignored under Windows.

val perm : permission list -> permission

Join permissions

val unix_perm : int -> permission

Create a permission from a Unix-style octal integer. See your favorite Unix documentation on chmod for more details.

  • raises Invalid_argument

    if given number outside the [0, 0o777] range

val set_permissions : string -> permission -> unit

Set the permissions on a file.

val chmod : string -> permission -> unit
Opening a file for reading
type open_in_flag = [
  1. | `create
  2. | `excl
    (*

    Fail if the file exists and `create is set

    *)
  3. | `text
    (*

    Open in ascii mode -- if this flag is not specified or if the operating system does not perform conversions, the file is opened in binary mode.

    *)
  4. | `nonblock
    (*

    Open in non-blocking mode

    *)
  5. | `mmap
    (*

    Open in memory-mapped mode (experimental)

    *)
]
val open_in : ?mode:open_in_flag list -> ?perm:permission -> string -> BatInnerIO.input

open_in file_name opens the file named file_name for reading.

Note You will need to close the file manually, with BatIO.close_in. An alternative is to call with_file_in instead of open_in.

Naming conventions for files are platform-dependent.

val with_file_in : ?mode:open_in_flag list -> ?perm:permission -> string -> (BatInnerIO.input -> 'a) -> 'a

with_file_in file_name f opens the file named file_name for reading, invokes f to process the contents of that file then, once f has returned or triggered an exception, closes the file before proceeding.

Opening a file for writing
type open_out_flag = [
  1. | `append
    (*

    Start writing at the end of the file rather than the start

    *)
  2. | `create
    (*

    Create the file if it does not exist

    *)
  3. | `trunc
    (*

    Empty the file if it already exists; on by default

    *)
  4. | `excl
    (*

    Fail if the file exists and `create is set

    *)
  5. | `text
    (*

    Open in ascii mode -- if this flag is not specified or if the operating system does not perform conversions, the file is opened in binary mode.

    *)
  6. | `nonblock
    (*

    Open in non-blocking mode

    *)
]

Flags governing file output; they correspond to the relevant flags to the POSIX open() call. The default flags are [`create; `trunc].

val open_out : ?mode:open_out_flag list -> ?perm:permission -> string -> unit BatInnerIO.output

open_out file_name opens the file named file_name for writing.

Note You will need to close the file manually, with BatIO.close_out. An alternative is to call with_file_out instead of open_out.

Naming conventions for files are platform-dependent.

val with_file_out : ?mode:open_out_flag list -> ?perm:permission -> string -> (unit BatInnerIO.output -> 'a) -> 'a

with_file_out file_name f opens the file named file_name for writing, invokes f to write onto that file then, once f has returned or triggered an exception, closes the file before proceeding.

Opening a temporary file for writing
type open_temporary_out_flag = [
  1. | open_out_flag
  2. | `delete_on_exit
    (*

    Should the file be deleted when program ends?

    *)
]
val open_temporary_out : ?mode:open_temporary_out_flag list -> ?prefix:string -> ?suffix:string -> ?temp_dir:string -> unit -> unit BatInnerIO.output * string

open_temporary_out () opens a new temporary file for writing.

  • parameter prefix

    a string which should appear at the start of your temporary file name (by default "ocaml")

  • parameter suffix

    a string which should appear at the end of your temporary file name (by default "tmp")

  • parameter temp_dir

    indicates what temp dir to use

  • returns

    The name of the file and the output for writing in it.

    Note You will need to close the file manually. An alternative is to call with_temporary_out instead of open_out.

    Naming conventions for files are platform-dependent.

val with_temporary_out : ?mode:open_temporary_out_flag list -> ?prefix:string -> ?suffix:string -> ?temp_dir:string -> (unit BatInnerIO.output -> string -> 'a) -> 'a

with_temporary_out f opens a new temporary file for writing, invokes f with to write onto that file then, once f has returned or triggered an exception, closes the file before proceeding.

  • parameter prefix

    a string which should appear at the start of your temporary file name (by default "ocaml")

  • parameter suffix

    a string which should appear at the end of your temporary file name (by default "tmp")

  • parameter temp_dir

    indicates what temp dir to use

  • returns

    The name of the file and the output for writing in it.

    Naming conventions for files are platform-dependent.