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72 lines
2.0 KiB
72 lines
2.0 KiB
关于调用os的命令
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```rust
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use std::process::Command;
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fn main() {
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let output = Command::new("rustc")
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.arg("--versn")
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.output().unwrap_or_else(|e| {
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panic!("failed to execute process: {}", e)
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});
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if output.status.success() {
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let s = String::from_utf8_lossy(&output.stdout);
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print!("rustc succeeded and stdout was:\n{}", s);
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} else {
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let s = String::from_utf8_lossy(&output.stderr);
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print!("rustc failed and stderr was:\n{}", s);
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}
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}
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```
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## Pipes
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The std::Child struct represents a running child process, and exposes the stdin, stdout and stderr handles for interaction with the underlying process via pipes.
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```rust
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use std::io::prelude::*;
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use std::process::{Command, Stdio};
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static PANGRAM: &'static str =
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"the quick brown fox jumped over the lazy dog\n";
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fn main() {
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// Spawn the `wc` command
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let process = match Command::new("wc")
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.stdin(Stdio::piped())
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.stdout(Stdio::piped())
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.spawn() {
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Err(why) => panic!("couldn't spawn wc: {}", why),
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Ok(process) => process,
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};
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// Write a string to the `stdin` of `wc`.
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//
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// `stdin` has type `Option<ChildStdin>`, but since we know this instance
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// must have one, we can directly `unwrap` it.
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match process.stdin.unwrap().write_all(PANGRAM.as_bytes()) {
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Err(why) => panic!("couldn't write to wc stdin: {}", why),
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Ok(_) => println!("sent pangram to wc"),
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}
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// Because `stdin` does not live after the above calls, it is `drop`ed,
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// and the pipe is closed.
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//
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// This is very important, otherwise `wc` wouldn't start processing the
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// input we just sent.
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// The `stdout` field also has type `Option<ChildStdout>` so must be unwrapped.
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let mut s = String::new();
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match process.stdout.unwrap().read_to_string(&mut s) {
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Err(why) => panic!("couldn't read wc stdout: {}", why),
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Ok(_) => print!("wc responded with:\n{}", s),
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}
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}
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```
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