Fix warnings on Linux

Makefile

@@ -0,0 +1,43 @@
+macos-5.5:
+	@echo
+	@echo === Building $@ ===
+	env DEVELOPER_DIR=/Applications/Xcode-13.2.1.app xcrun swift build
+
+macos-5.6:
+	@echo
+	@echo === Building $@ ===
+	env DEVELOPER_DIR=/Applications/Xcode-13.4.1.app xcrun swift build
+
+macos-5.7:
+	@echo
+	@echo === Building $@ ===
+	env DEVELOPER_DIR=/Applications/Xcode-14.2.0.app xcrun swift build
+
+linux-5.5:
+	@echo
+	@echo === Building $@ ===
+	docker run --rm -v "$(PWD)":/host -w /host "swift:5.5-focal" swift build
+
+linux-5.6:
+	@echo
+	@echo === Building $@ ===
+	docker run --rm -v "$(PWD)":/host -w /host "swift:5.6-focal" swift build
+
+linux-5.7:
+	@echo
+	@echo === Building $@ ===
+	docker run --rm -v "$(PWD)":/host -w /host "swift:5.7-focal" swift build
+
+linux: \
+	linux-5.5 \
+	linux-5.6 \
+	linux-5.7
+
+macos: \
+	macos-5.5 \
+	macos-5.6 \
+	macos-5.7
+
+all: \
+	macos \
+	linux

Sources/ShellOut.swift

@@ -398,7 +398,11 @@ extension ShellOutCommand {
 
 private extension Process {
     @discardableResult func launchBash(with command: String, outputHandle: FileHandle? = nil, errorHandle: FileHandle? = nil, environment: [String : String]? = nil) throws -> String {
+#if os(Linux)
+        executableURL = URL(fileURLWithPath: "/bin/bash")
+#else
         launchPath = "/bin/bash"
+#endif
         arguments = ["-c", command]
 
         if let environment = environment {
@@ -438,7 +442,11 @@ private extension Process {
         }
         #endif
 
+#if os(Linux)
+        try run()
+#else
         launch()
+#endif
 
         #if os(Linux)
         outputQueue.sync {