val argv: string array

The command line arguments given to the process. The first element is the command name used to invoke the program. The following elements are the command-line arguments given to the program.

val file_exists: string -> bool

Test if a file with the given name exists.

val remove: string -> unit

Remove the given file name from the file system.

val rename: string -> string -> unit

Rename a file. The first argument is the old name and the second is the new name.

val getenv: string -> string

Return the value associated to a variable in the process environment. Raise Not_found if the variable is unbound.

val command: string -> int

Execute the given shell command and return its exit code.

val time: unit -> float

Return the processor time, in seconds, used by the program since the beginning of execution.

val chdir: string -> unit

Change the current working directory of the process.

val getcwd: unit -> string

Return the current working directory of the process.

val interactive: bool ref

This reference is initially set to false in standalone programs and to true if the code is being executed under the interactive toplevel system ocaml.

val os_type: string

Operating system currently executing the Caml program. One of "Unix", "Win32", "Cygwin" or "MacOS".

val word_size: int

Size of one word on the machine currently executing the Caml program, in bits: 32 or 64.

val max_string_length: int

Maximum length of a string.

val max_array_length: int

Maximum length of an array.

type signal_behavior =
    Signal_default
  | Signal_ignore
  | Signal_handle of (int -> unit)

What to do when receiving a signal:
Signal_default: take the default behavior (usually: abort the program)
Signal_ignore: ignore the signal
Signal_handle f: call function f, giving it the signal number as argument