Module `OS.Cmd`

Running commands.

Command existence

val exists : Cmd.t -> bool result: exists cmd is true if the executable of cmd can be found in the path and false otherwise.

val must_exist : Cmd.t -> Cmd.t result: must_exist cmd is cmd if the executable of cmd can be found in the path and an error otherwise.

Running commands

val run : ?⁠err:fpath -> Cmd.t -> unit result: run cmd runs the command cmd. std{i,o,err} are connected to the invoking process' standard channels. If err is specified stderr is redirected to the given file (e.g. File.null).

val run_status : ?⁠err:fpath -> Cmd.t -> [ `Exited of int ] result: run_status cmd is like Running commands, but doesn't error on non-zero exit status.

Capturing standard output

type run_status = Cmd.t * [ `Exited of int ]: The type for run statuses, the command that was run and the run status.

val success : ('a * run_status) result -> 'a result

success r is:

Ok v if r = Ok (v, (_, `Exited 0))
Error _ otherwise. Non `Exited 0 statuses are turned into an error message.

type run_out: The type for representing the standard output of a command run.

val out_string : ?⁠trim:bool -> run_out -> (string * run_status) result: out_string ~trim o captures the standard output o as a string. If trim is true (default) the result is passed through String.trim.

val out_lines : ?⁠trim:bool -> run_out -> (string list * run_status) result: out_lines ~trim is like out_string but the result is cut on newlines ('\n').

val out_file : fpath -> run_out -> (unit * run_status) result: out_file f o writes the standard output o to file f.

val out_stdout : run_out -> (unit * run_status) result: out_stdout o redirects the standard output o to the current process standard output.

val to_string : ?⁠trim:bool -> run_out -> string result: to_string is (out_string ?trim o |> success).

val to_lines : ?⁠trim:bool -> run_out -> string list result: to_lines ?trim o is (out_string ?trim o |> success).

val to_file : fpath -> run_out -> unit result: to_file f o is (out_file f o |> success)

val run_out : ?⁠err:fpath -> Cmd.t -> run_out: run_out cmd represents the standard output of the command run cmd. std{i,err} are connected to the invoking prcoess stream and standard output can be consumed with to_string, to_lines or to_file. If err is specified stderr is redirected to the given file.