Support shelling out to a series of commands, optionally at a given path

This addition to ShellOut makes it easier to run a series of commands, without
having to manually string them together using ‘&&’. It also enables you to
easily run a shell command at a given path, without having to ‘cd’ to it first.

Sources/ShellOut.swift

@@ -13,19 +13,39 @@ import Foundation
  *
  *  - parameter command: The command to run
  *  - parameter arguments: The arguments to pass to the command
+ *  - parameter path: The path to execute the commands at (defaults to current folder)
  *
  *  - returns: The output of running the command
  *  - throws: `ShellOutError` in case the command couldn't be performed, or it returned an error
  *
  *  Use this function to "shell out" in a Swift script or command line tool
- *  For example: `shellOut(to: "mkdir", arguments: ["NewFolder"])`
+ *  For example: `shellOut(to: "mkdir", arguments: ["NewFolder"], at: "~/CurrentFolder")`
  */
-@discardableResult public func shellOut(to command: String, arguments: [String] = []) throws -> String {
+@discardableResult public func shellOut(to command: String,
+                                        arguments: [String] = [],
+                                        at path: String = ".") throws -> String {
     let process = Process()
-    let command = "\(command) \(arguments.joined(separator: " "))"
+    let command = "cd \"\(path)\" && \(command) \(arguments.joined(separator: " "))"
     return try process.launchBash(with: command)
 }
 
+/**
+ *  Run a series of shell commands using Bash
+ *
+ *  - parameter commands: The commands to run
+ *  - parameter path: The path to execute the commands at (defaults to current folder)
+ *
+ *  - returns: The output of running the command
+ *  - throws: `ShellOutError` in case the command couldn't be performed, or it returned an error
+ *
+ *  Use this function to "shell out" in a Swift script or command line tool
+ *  For example: `shellOut(to: ["mkdir NewFolder", "cd NewFolder"], at: "~/CurrentFolder")`
+ */
+@discardableResult public func shellOut(to commands: [String], at path: String = ".") throws -> String {
+    let command = commands.joined(separator: " && ")
+    return try shellOut(to: command, at: path)
+}
+
 // Error type thrown by the `shellOut()` function, in case the given command failed
 public struct ShellOutError: Swift.Error {
     /// The error message that was returned through `STDERR`

Tests/ShellOutTests/ShellOutTests.swift

@@ -23,6 +23,35 @@ class ShellOutTests: XCTestCase {
         XCTAssertEqual(echo, "Hello world")
     }
 
+    func testSingleCommandAtPath() throws {
+        try shellOut(to: "echo \"Hello\" > \(NSTemporaryDirectory())ShellOutTests-SingleCommand.txt")
+
+        let textFileContent = try shellOut(to: "cat ShellOutTests-SingleCommand.txt",
+                                           at: NSTemporaryDirectory())
+
+        XCTAssertEqual(textFileContent, "Hello")
+    }
+
+    func testSeriesOfCommands() throws {
+        let echo = try shellOut(to: ["echo \"Hello\"", "echo \"world\""])
+        XCTAssertEqual(echo, "Hello\nworld")
+    }
+
+    func testSeriesOfCommandsAtPath() throws {
+        try shellOut(to: [
+            "cd \(NSTemporaryDirectory())",
+            "mkdir -p ShellOutTests",
+            "echo \"Hello again\" > ShellOutTests/MultipleCommands.txt"
+        ])
+
+        let textFileContent = try shellOut(to: [
+            "cd ShellOutTests",
+            "cat MultipleCommands.txt"
+        ], at: NSTemporaryDirectory())
+
+        XCTAssertEqual(textFileContent, "Hello again")
+    }
+
     func testThrowingError() {
         do {
             try shellOut(to: "cd", arguments: ["notADirectory"])