[−][src]Struct subprocess::Exec
A builder for Popen
instances, providing control and
convenience methods.
Exec
provides a builder API for Popen::create
, and
includes convenience methods for capturing the output, and for
connecting subprocesses into pipelines.
Examples
Execute an external command and wait for it to complete:
let exit_status = Exec::cmd("umount").arg(dirname).join()?;
Execute the command using the OS shell, like C's system
:
Exec::shell("shutdown -h now").join()?;
Start a subprocess and obtain its output as a Read
trait object,
like C's popen
:
let stream = Exec::cmd("ls").stream_stdout()?; // call stream.read_to_string, construct io::BufReader(stream), etc.
Capture the output of a command:
let out = Exec::cmd("ls") .stdout(Redirection::Pipe) .capture()? .stdout_str();
Redirect errors to standard output, and capture both in a single stream:
let out_and_err = Exec::cmd("ls") .stdout(Redirection::Pipe) .stderr(Redirection::Merge) .capture()? .stdout_str();
Provide input to the command and read its output:
let out = Exec::cmd("sort") .stdin("b\nc\na\n") .stdout(Redirection::Pipe) .capture()? .stdout_str(); assert!(out == "a\nb\nc\n");
Methods
impl Exec
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pub fn cmd(command: impl AsRef<OsStr>) -> Exec
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Constructs a new Exec
, configured to run command
.
The command will be run directly in the OS, without an
intervening shell. To run it through a shell, use
Exec::shell
instead.
By default, the command will be run without arguments, and none of the standard streams will be modified.
pub fn shell(cmdstr: impl AsRef<OsStr>) -> Exec
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Constructs a new Exec
, configured to run cmdstr
with
the system shell.
subprocess
never spawns shells without an explicit
request. This command requests the shell to be used; on
Unix-like systems, this is equivalent to
Exec::cmd("sh").arg("-c").arg(cmdstr)
. On Windows, it
runs Exec::cmd("cmd.exe").arg("/c")
.
shell
is useful for porting code that uses the C
system
function, which also spawns a shell.
When invoking this function, be careful not to interpolate
arguments into the string run by the shell, such as
Exec::shell(format!("sort {}", filename))
. Such code is
prone to errors and, if filename
comes from an untrusted
source, to shell injection attacks. Instead, use
Exec::cmd("sort").arg(filename)
.
pub fn arg(self, arg: impl AsRef<OsStr>) -> Exec
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Appends arg
to argument list.
pub fn args(self, args: &[impl AsRef<OsStr>]) -> Exec
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Extends the argument list with args
.
pub fn detached(self) -> Exec
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Specifies that the process is initially detached.
A detached process means that we will not wait for the process to finish when the object that owns it goes out of scope.
pub fn env_clear(self) -> Exec
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Clears the environment of the subprocess.
When this is invoked, the subprocess will not inherit the environment of this process.
pub fn env(self, key: impl AsRef<OsStr>, value: impl AsRef<OsStr>) -> Exec
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Sets an environment variable in the child process.
If the same variable is set more than once, the last value is used.
Other environment variables are by default inherited from
the current process. If this is undesirable, call
env_clear
first.
pub fn env_extend(self, vars: &[(impl AsRef<OsStr>, impl AsRef<OsStr>)]) -> Exec
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Sets multiple environment variables in the child process.
The keys and values of the variables are specified by the slice. If the same variable is set more than once, the last value is used.
Other environment variables are by default inherited from
the current process. If this is undesirable, call
env_clear
first.
pub fn env_remove(self, key: impl AsRef<OsStr>) -> Exec
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Removes an environment variable from the child process.
Other environment variables are inherited by default.
pub fn cwd(self, dir: impl AsRef<Path>) -> Exec
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Specifies the current working directory of the child process.
If unspecified, the current working directory is inherited from the parent.
pub fn stdin(self, stdin: impl Into<InputRedirection>) -> Exec
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Specifies how to set up the standard input of the child process.
Argument can be:
- a
Redirection
; - a
File
, which is a shorthand forRedirection::File(file)
; - a
Vec<u8>
or&str
, which will set up aRedirection::Pipe
for stdin, making sure thatcapture
feeds that data into the standard input of the subprocess; NullFile
, which will redirect the standard input to read from/dev/null
.
pub fn stdout(self, stdout: impl Into<OutputRedirection>) -> Exec
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Specifies how to set up the standard output of the child process.
Argument can be:
- a
Redirection
; - a
File
, which is a shorthand forRedirection::File(file)
; NullFile
, which will redirect the standard output to go to/dev/null
.
pub fn stderr(self, stderr: impl Into<OutputRedirection>) -> Exec
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Specifies how to set up the standard error of the child process.
Argument can be:
- a
Redirection
; - a
File
, which is a shorthand forRedirection::File(file)
; NullFile
, which will redirect the standard error to go to/dev/null
.
pub fn popen(self) -> PopenResult<Popen>
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Starts the process, returning a Popen
for the running process.
pub fn join(self) -> PopenResult<ExitStatus>
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Starts the process, waits for it to finish, and returns the exit status.
This method will wait for as long as necessary for the
process to finish. If a timeout is needed, use
popen()?.wait_timeout(...)
instead.
pub fn stream_stdout(self) -> PopenResult<impl Read>
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Starts the process and returns a value implementing the Read
trait that reads from the standard output of the child process.
This will automatically set up
stdout(Redirection::Pipe)
, so it is not necessary to do
that beforehand.
When the trait object is dropped, it will wait for the
process to finish. If this is undesirable, use
detached()
.
pub fn stream_stderr(self) -> PopenResult<impl Read>
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Starts the process and returns a value implementing the Read
trait that reads from the standard error of the child process.
This will automatically set up
stderr(Redirection::Pipe)
, so it is not necessary to do
that beforehand.
When the trait object is dropped, it will wait for the
process to finish. If this is undesirable, use
detached()
.
pub fn stream_stdin(self) -> PopenResult<impl Write>
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Starts the process and returns a value implementing the Write
trait that writes to the standard input of the child process.
This will automatically set up stdin(Redirection::Pipe)
,
so it is not necessary to do that beforehand.
When the trait object is dropped, it will wait for the
process to finish. If this is undesirable, use
detached()
.
pub fn communicate(self) -> PopenResult<Communicator>
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Starts the process and returns a Communicator
handle.
This is a lower-level API that offers more choice in how
communication is performed, such as read size limit and timeout,
equivalent to Popen::communicate
.
Unlike capture()
, this method doesn't wait for the process to
finish, effectively detaching it.
pub fn capture(self) -> PopenResult<CaptureData>
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Starts the process, collects its output, and waits for it to finish.
The return value provides the standard output and standard error as bytes or optionally strings, as well as the exit status.
Unlike Popen::communicate
, this method actually waits
for the process to finish, rather than simply waiting for
its standard streams to close. If this is undesirable,
use detached()
.
pub fn to_cmdline_lossy(&self) -> String
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Show Exec as command-line string quoted in the Unix style.
Trait Implementations
impl BitOr<Exec> for Exec
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type Output = Pipeline
The resulting type after applying the |
operator.
fn bitor(self, rhs: Exec) -> Pipeline
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Create a Pipeline
from self
and rhs
.
impl BitOr<Exec> for Pipeline
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type Output = Pipeline
The resulting type after applying the |
operator.
fn bitor(self, rhs: Exec) -> Pipeline
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Append a command to the pipeline and return a new pipeline.
impl Clone for Exec
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fn clone(&self) -> Exec
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Returns a copy of the value.
This method is guaranteed not to fail as long as none of
the Redirection
values contain a Redirection::File
variant. If a redirection to File
is present, cloning
that field will use File::try_clone
method, which
duplicates a file descriptor and can (but is not likely
to) fail. In that scenario, Exec::clone
panics.
fn clone_from(&mut self, source: &Self)
1.0.0[src]
impl Debug for Exec
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Auto Trait Implementations
impl !RefUnwindSafe for Exec
impl !Send for Exec
impl !Sync for Exec
impl Unpin for Exec
impl UnwindSafe for Exec
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,