diff --git a/PartnerCtl/src/main/java/work/slhaf/partner/ctl/support/command.kt b/PartnerCtl/src/main/java/work/slhaf/partner/ctl/support/command.kt
new file mode 100644
index 00000000..0b5a6e05
--- /dev/null
+++ b/PartnerCtl/src/main/java/work/slhaf/partner/ctl/support/command.kt
@@ -0,0 +1,92 @@
+package work.slhaf.partner.ctl.support
+
+import java.io.InputStream
+import java.nio.charset.Charset
+import java.nio.charset.StandardCharsets
+import java.nio.file.Path
+import java.util.concurrent.Executors
+import java.util.concurrent.TimeUnit
+
+/**
+ * Result of a completed external command.
+ */
+data class CommandResult(
+    val command: List<String>,
+    val exitCode: Int,
+    val stdout: String,
+    val stderr: String,
+) {
+    val success: Boolean get() = exitCode == 0
+}
+
+/**
+ * Runs a command and captures stdout/stderr separately.
+ */
+fun runCommand(
+    command: List<String>,
+    workingDirectory: Path? = null,
+    environment: Map<String, String> = emptyMap(),
+    timeoutSeconds: Long? = null,
+    charset: Charset = StandardCharsets.UTF_8,
+): CommandResult {
+    require(command.isNotEmpty()) { "command must not be empty" }
+
+    val process = ProcessBuilder(command)
+        .apply {
+            if (workingDirectory != null) directory(workingDirectory.toFile())
+            environment().putAll(environment)
+        }
+        .start()
+
+    val executor = Executors.newFixedThreadPool(2)
+    try {
+        val stdout = executor.submit<String> { process.inputStream.readText(charset) }
+        val stderr = executor.submit<String> { process.errorStream.readText(charset) }
+
+        val finished = if (timeoutSeconds == null) {
+            process.waitFor()
+            true
+        } else {
+            process.waitFor(timeoutSeconds, TimeUnit.SECONDS)
+        }
+
+        if (!finished) {
+            process.destroyForcibly()
+            process.waitFor()
+        }
+
+        return CommandResult(
+            command = command,
+            exitCode = if (finished) process.exitValue() else -1,
+            stdout = stdout.get(),
+            stderr = stderr.get(),
+        )
+    } finally {
+        executor.shutdownNow()
+    }
+}
+
+/**
+ * Runs a command with stdout/stderr/stdin inherited from current process.
+ */
+fun inheritCommand(
+    command: List<String>,
+    workingDirectory: Path? = null,
+    environment: Map<String, String> = emptyMap(),
+): Int {
+    require(command.isNotEmpty()) { "command must not be empty" }
+
+    val process = ProcessBuilder(command)
+        .apply {
+            if (workingDirectory != null) directory(workingDirectory.toFile())
+            environment().putAll(environment)
+            inheritIO()
+        }
+        .start()
+
+    return process.waitFor()
+}
+
+private fun InputStream.readText(charset: Charset): String {
+    return bufferedReader(charset).use { it.readText() }
+}