module Shell:sig..end
call, signal handlers
are automatically installed by Shell_sys.install_job_handlers, unless
this installation has already been performed. You can configure these
handlers by Shell_sys.configure_job_handlers. The handlers remain
in effect even after call returns.
Note that this has a global side effect on the whole process, because
there is only one set of signal handlers.
Shell_sys.job abstraction.exception Subprocess_error of (string * Unix.process_status) list
type producer
type consumer
type assignment
val command : ?cmdname:string ->
?arguments:string array ->
?chdir:string ->
?environment:Shell_sys.environment ->
?descriptors:Unix.file_descr list ->
?assignments:assignment list -> string -> Shell_sys.commandcall. The anonymous
string argument is the name of the executable to invoke. If the name
contains a '/', it is simply interpreted as the filename of the
executable. Otherwise the command is searched in the current PATH.
cmdname : The name of the command passed in argv[0]. By
default, this argument is derived from the name of the executable.arguments : The arguments of the command (starting with the
first real argument, skipping cmdname). By default [] .chdir : Before the command is executed it is changed to
this directory.environment : The environment of the command. By default, the
current environmentdescriptors : The list of file descriptors to share with the
current process; all other file descriptors will be closed.
By default, [stdin; stdout; stderr] .assignments : The list of descriptor assignments. The assignments
are applied one after the other. By default empty.val cmd : ?cmdname:string ->
?chdir:string ->
?environment:Shell_sys.environment ->
?descriptors:Unix.file_descr list ->
?assignments:assignment list ->
string -> string list -> Shell_sys.commandcommand but with a slightly different interface: Use
cmd "ls" [ "/dir/file" ]
instead of
command ~arguments:[|"/dir/file"|] "ls"
The named arguments have the same meanings as in command.
val call : ?ignore_error_code:bool ->
?mode:Shell_sys.group_mode ->
?stdin:producer ->
?stdout:consumer ->
?stderr:consumer -> Shell_sys.command list -> unit [c1;c2;...;cN] is passed, this corresponds to the pipeline
c1 | c2 | ... | cN (in shell notation).
The function returns normally if all processes can be started and
terminate regularly with exit code 0. If a process terminates with
some other exit code, and ignore_error_code is set, the function
returns normally, too. The latter does not apply if a process terminates
because of a signal (which triggers always the exception
Subprocess_error).
If a process terminates with an exit code other than 0 and
ignore_error_code is not set (the default), or if a process is
terminated because of a signal, the exception Subprocess_error
will be raised. For every command the process result is included
in the exception argument.
If a process cannot be started (e.g. because of insufficient
resources), the function will try to shut down the already running
part of the pipeline by sending SIGTERM to these processes.
It is not checked whether the processes actually terminate (no
"wait" for them); an appropriate exception will be raised.
In the case that it is not even possible to perform these cleanup
actions, the exception Shell_sys.Fatal_error will be raised.
When the function raises an exception other than Subprocess_error,
a serious error condition has happened, and it is recommended
to exit the program as soon as possible.
ignore_error_code : If true, exit codes other than 0 of the
subprocesses are ignored. This does not apply to signals, however.
By default false.mode : See Shell_sys.run_job for a detailed description
of this parameter. By default Same_as_caller.stdin : If present, the first process of the pipeline reads
input data from this procucer. By default, there is no such
producer.stdout : If present, the last process of the pipeline writes
output data to this consumer. By default, there is no such
consumer.stderr : If present, all processes of the pipeline write
their error messages to this consumer. By default, there is no
such consumer.val setup_job : ?stdin:producer ->
?stdout:consumer ->
?stderr:consumer ->
Shell_sys.command list -> Shell_sys.job * Unix.file_descr listcall, but does not execute it. In addition to
the job, the file descriptors are returned that must be closed
when the job is done.val postprocess_job : ?ignore_error_code:bool -> Shell_sys.job_instance -> unitSubprocess_error when there is an error that cannot be ignored.
As error conditions are considered non-zero exit codes of any
called processes, or signals terminating any of the called processes.
ignore_error_code : If true, exit codes other than 0 of the
subprocesses are ignored. This does not apply to signals, however.
By default false.val assign : src:Unix.file_descr -> target:Unix.file_descr -> assignmentsrc or reading from src
will actually write to target or read from target
(i.e., the target descriptor is duplicated and replaces
the src descriptor just before the process is launched.)
Note that assignments work only if the descriptors are shared
with the called process, so they must also be contained in the
descriptors list of command or cmd. Furthermore, the
close-on-exec flag must not be set.
val (>&) : Unix.file_descr -> Unix.file_descr -> assignmentassign, but infix notation. For example,
stdout >& stderr creates an assignment such that all output
to stdout is redirected to stderr.
f >& g is the same as assign ~src:f target:g. It should
be used for output assignments (as in the Bourne shell).
val (<&) : Unix.file_descr -> Unix.file_descr -> assignmentassign, but infix notation. For example,
stdin <& f creates an assignment such that the called process
reads from the open file descriptor f.
f <& g is the same as assign ~src:f target:g. It should
be used for input assignments (as in the Bourne shell).
val assigned_pair : assignment -> Unix.file_descr * Unix.file_descr(target,src).val stdin : Unix.file_descr
val stdout : Unix.file_descr
val stderr : Unix.file_descrval from_string : ?pos:int -> ?len:int -> ?epipe:(unit -> unit) -> string -> producers. After these data
are sent, the pipeline is closed.
pos : The position in s where the data slice to transfer begins.
By default 0.len : The length of the data slice to transfer. By default,
all bytes from the start position pos to the end of the
string are taken.epipe : This function is called when the pipeline breaks
(EPIPE). Default: the empty function. EPIPE exceptions are
always caught, and implicitly handled by closing the pipeline.val from_stream : ?epipe:(unit -> unit) -> string Stream.t -> producer
epipe : This function is called when the pipeline breaks
(EPIPE). Default: the empty function. EPIPE exceptions are
always caught, and implicitly handled by closing the pipeline.val from_function : producer:(Unix.file_descr -> bool) -> unit -> producerShell_sys.add_producer for the meaning of the producer
function.val from_file : string -> producerval from_fd : Unix.file_descr -> producerval from_dev_null : producer/dev/null.val to_buffer : Buffer.t -> consumerval to_function : consumer:(Unix.file_descr -> bool) -> unit -> consumerShell_sys.add_consumer for the meaning of the consumer
function.val to_file : ?append:bool -> string -> consumerappend is given, the file is
truncated and overwritten. If append is true, the data are
appended to the file. By default, append is false.val to_fd : Unix.file_descr -> consumerval to_dev_null : consumer/dev/null.
The following examples show toploop sessions using Shell.
Call the command "ls" without redirection:
# call [ command "ls" ];;
IDEAS s1.ml~ shell.mli~ shell_sys.ml~ unix_exts.ml
META shell.a shell.ml~ shell_sys.o unix_exts.mli
Makefile shell.cma shell_sys.cmi t unix_exts.mli~
Makefile~ shell.cmi shell_sys.cmo testjob unix_exts.ml~
depend shell.cmo shell_sys.cmx testjob~ unix_exts.o
libshell.a shell.cmxa shell_sys.ml unix_exts.cmi unix_exts_c.c
log shell.ml shell_sys.mli unix_exts.cmo unix_exts_c.c~
s1.ml shell.mli shell_sys.mli~ unix_exts.cmx unix_exts_c.o
\- : unit = ()
The output of "ls" is collected in the buffer b:
# let b = Buffer.create 10;;
val b : Buffer.t = <abstr>
# call ~stdout:(to_buffer b) [ command "ls" ];;
\- : unit = ()
# Buffer.contents b;;
\- : string =
"IDEAS\nMETA\nMakefile\nMakefile~\ndepend\n..."
Because "/a" does not exist, "ls" will fail. The command writes the message to stderr (not redirected here), and returns with an exit code of 1, triggering an exception:
# call [ command ~arguments:[| "/a" |] "ls" ];;
/bin/ls: /a: No such file or directory
Uncaught exception: Shell.Subprocess_error ["/bin/ls", Unix.WEXITED 1].
Here, the message written to stderr is collected in b:
# Buffer.clear b;;
\- : unit = ()
# call ~stderr:(to_buffer b) [ command ~arguments:[| "/a" |] "ls" ];;
Uncaught exception: Shell.Subprocess_error ["/bin/ls", Unix.WEXITED 1].
# Buffer.contents b;;
\- : string = "/bin/ls: /a: No such file or directory\n"
Here, the output of "cat" becomes the input of "sort":
# call [ command ~arguments:[|"META"|] "cat"; command "sort" ];;
archive(byte) = "shell.cma"
archive(native) = "shell.cmxa"
description = "Unix shell functions"
linkopts = "-cclib -lshell"
requires = "unix str"
version = "0.0"
\- : unit = ()
The same, but the output of "sort" is collected in the buffer b:
# Buffer.clear b;;
\- : unit = ()
# call ~stdout:(to_buffer b) [ command ~arguments:[|"META"|] "cat"; command "sort" ];;
\- : unit = ()
# Buffer.contents b;;
\- : string =
"archive(byte) = \"shell.cma\"\narchive(native) = \"shell.cmxa\"\ndescription = \"Unix shell functions\"\nlinkopts = \"-cclib -lshell\"\nrequires = \"unix str\"\nversion = \"0.0\"\n"
The contents of the string s are written to the input of "sort":
# let s = "f\na\nd\nc\n";;
val s : string = "f\na\nd\nc\n"
# call ~stdin:(from_string s) [ command "sort" ];;
a
c
d
f
\- : unit = ()
It is possible to have several redirections. Here, the string s is
sorted by "sort", and the output is collected in the buffer b:
# Buffer.clear b;;
\- : unit = ()
# call ~stdout:(to_buffer b) ~stdin:(from_string s) [ command "sort" ];;
\- : unit = ()
# Buffer.contents b;;
\- : string = "a\nc\nd\nf\n"
Here, the output and errors of "ls" are both collected in the buffer
b:
# Buffer.clear b;;
\- : unit = ()
# call ~stdout:(to_buffer b)
[ command
~assignments:[ stderr >& stdout ]
~arguments:[| "/a" |]
"ls" ];;
Uncaught exception: Shell.Subprocess_error ["/bin/ls", Unix.WEXITED 1].
# Buffer.contents b;;
\- : string = "/bin/ls: /a: No such file or directory\n"
Of course, all features can be combined arbitrarily.
Note that error reporting is better than in a traditional shell, because the exit codes of all started commands are returned. (Shells usually only return the exit code of the last command of a pipeline.)
For non-standard pipelines, you can also use the functions in
Shell_sys. "call" is a simple concatenation of Shell_sys invocations.