Module `Bos.Cmd`

Command lines.

Both command lines and command line fragments using the same are represented with the same type.

When a command line is run, the first element of the line defines the program name and each other element is an argument that will be passed as is in the program's argv array: no shell interpretation or any form of argument quoting and/or concatenation occurs.

See examples.

Command line fragments

type t

The type for command line fragments.

val v : string -> t

v cmd is a new command line (or command line fragment) whose first argument is cmd.

val empty : t

empty is an empty command line.

val is_empty : t -> bool

is_empty l is true iff l is empty.

val (%) : t -> string -> t

l % arg adds arg to the command line l.

val (%%) : t -> t -> t

l %% frag appends the line fragment frag to l.

val add_arg : t -> string -> t

add_arg l arg is l % arg.

val add_args : t -> t -> t

add_args l frag is l %% frag.

val on : bool -> t -> t

on bool line is line if bool is true and empty otherwise.

val p : Fpath.t -> string

p is Fpath.to_string. This combinator makes path argument specification brief.

Command lines

val line_tool : t -> string option

line_tool l is l's first element, usually the executable tool name or file path.

val get_line_tool : t -> string

get_line_tool l is like line_tool but raises Invalid_argument if there's no first element.

val line_args : t -> string list

line_args is l's command line arguments, the elements of l without the command name.

val line_exec : t -> string option

deprecated
Use line_tool instead.

val get_line_exec : t -> string

deprecated
Use get_line_tool instead.

Predicates and comparison

val equal : t -> t -> bool

equal l l' is true iff l and l' are litterally equal.

val compare : t -> t -> int

compare l l' is a total order on command lines.

Conversions and pretty printing

val of_string : string -> (t, Rresult.R.msg) Rresult.result

of_string s tokenizes s into a command line. The tokens are recognized according to the token production of the following grammar which should be mostly be compatible with POSIX shell tokenization.

white   ::= ' ' | '\t' | '\n' | '\x0B' | '\x0C' | '\r'
squot   ::= '\''
dquot   ::= '\"'
bslash  ::= '\\'
tokens  ::= white+ tokens | token tokens | ϵ
token   ::= ([^squot dquot white] | squoted | dquoted) token | ϵ
squoted ::= squot [^squot]* squot
dquoted ::= dquot (qchar | [^dquot])* dquot
qchar   ::= bslash (bslash | dquot | '$' | '`' | '\n')

qchar are substitued by the byte they escape except for '\n' which removes the backslash and newline from the byte stream. squoted and dquoted represent the bytes they enclose.

val to_string : t -> string

to_string l converts l to a string that can be passed to the command(3) POSIX system call.

val to_list : t -> string list

to_list l is l as a list of strings.

val of_list : ?slip:string -> string list -> t

of_list ?slip l is a command line from the list of arguments l. If slip is specified it is added on the command line before each element of l.

val of_values : ?slip:string -> ('a -> string) -> 'a list -> t

of_values ?slip conv l is like of_list but acts on a list of values, each converted to an argument with conv.

val pp : Format.formatter -> t -> unit

pp ppf l formats an unspecified representation of l on ppf.

val dump : Format.formatter -> t -> unit

dump ppf l dumps and unspecified representation of l on ppf.

Examples

let ls path = Cmd.(v "ls" % "-a" % p path)

let tar archive path = Cmd.(v "tar" % "-cvf" % p archive % p path)

let opam cmd = Cmd.(v "opam" % cmd)

let opam_install pkgs = Cmd.(opam "install" %% of_list pkgs)

let ocamlc ?(debug = false) file =
  Cmd.(v "ocamlc" % "-c" %% on debug (v "-g") % p file)

let ocamlopt ?(profile = false) ?(debug = false) incs file =
  let profile = Cmd.(on profile @@ v "-p") in
  let debug = Cmd.(on debug @@ v "-g") in
  let incs = Cmd.of_list ~slip:"-I" incs in
  Cmd.(v "ocamlopt" % "-c" %% debug %% profile %% incs % p file)

package bos