Testing Command

commandtest/.gitignore

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+script.log

commandtest/Cargo.toml

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+[package]
+name = "commandtest"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

commandtest/README.md

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+# CommandTest
+
+Playing a bit with `Command`, trying to send the output of a command to a file
+(easy) while capturing it at the same time, looking for some special strings
+(hard).

commandtest/src/main.rs

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+use std::ffi::OsString;
+use std::fs::File;
+use std::path::PathBuf;
+use std::process::Command;
+
+fn search_in_path(name: &str) -> Option<PathBuf> {
+    let path = std::env::var_os("PATH").unwrap_or_else(OsString::new);
+    std::env::split_paths(&path).find_map(|dir| {
+        let full_path = dir.join(name);
+        if full_path.is_file() {
+            Some(full_path)
+        } else {
+            None
+        }
+    })
+}
+
+fn main() {
+    // this requires always running with `cargo run`
+    let base = PathBuf::from(env!("CARGO_MANIFEST_DIR"));
+    let log_file = File::create("script.log").unwrap();
+    let the_script = base.join("src").join("the_script.sh");
+    let bash = search_in_path("bash").unwrap();
+
+    let mut cmd = Command::new(bash)
+        .arg(the_script)
+        .stdout(log_file)
+        .spawn()
+        .unwrap();
+
+    cmd.wait().unwrap();
+}

commandtest/src/the_script.sh

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+#!/usr/bin/env bash
+
+echo "Hello, I'm a script!"
+echo "I write stuff in the output."
+echo "Everything should go to a file."
+echo "But also, you need to capture this:"
+echo "WARNING: This is a warning"
+echo "   It continues if the line starts with spaces"
+echo "   And keeps going till there are no more spaces-prefixes"
+echo "Like this."
+echo "Then you're good to go."