add zsh shell path option

Sources/ShellOut.swift

@@ -33,14 +33,16 @@ import Dispatch
     at path: String = ".",
     process: Process = .init(),
     outputHandle: FileHandle? = nil,
-    errorHandle: FileHandle? = nil
+    errorHandle: FileHandle? = nil,
+    shellType: ShellType = .bashPath
 ) throws -> String {
     let command = "cd \(path.escapingSpaces) && \(command) \(arguments.joined(separator: " "))"
 
     return try process.launchBash(
         with: command,
         outputHandle: outputHandle,
-        errorHandle: errorHandle
+        errorHandle: errorHandle,
+        shellType: shellType
     )
 }
 
@@ -101,14 +103,16 @@ import Dispatch
     at path: String = ".",
     process: Process = .init(),
     outputHandle: FileHandle? = nil,
-    errorHandle: FileHandle? = nil
+    errorHandle: FileHandle? = nil,
+    shellType: ShellType = .bashPath
 ) throws -> String {
     return try shellOut(
         to: command.string,
         at: path,
         process: process,
         outputHandle: outputHandle,
-        errorHandle: errorHandle
+        errorHandle: errorHandle,
+        shellType: shellType
     )
 }
 
@@ -123,6 +127,12 @@ public struct ShellOutCommand {
     }
 }
 
+/// Used to specify the path of which shell to use. Default is set to Bash.
+public enum ShellType: String {
+    case bashPath = "/bin/bash"
+    case zshPath = "/bin/zsh"
+}
+
 /// Git commands
 public extension ShellOutCommand {
     /// Initialize a git repository
@@ -379,8 +389,9 @@ extension ShellOutError: LocalizedError {
 // MARK: - Private
 
 private extension Process {
-    @discardableResult func launchBash(with command: String, outputHandle: FileHandle? = nil, errorHandle: FileHandle? = nil) throws -> String {
-        launchPath = "/bin/bash"
+    @discardableResult func launchBash(with command: String, outputHandle: FileHandle? = nil, errorHandle: FileHandle? = nil, shellType: ShellType = .bashPath) throws -> String {
+        // Default shell path is set to Bash
+        launchPath = shellType.rawValue
         arguments = ["-c", command]
 
         // Because FileHandle's readabilityHandler might be called from a

Tests/ShellOutTests/ShellOutTests+Linux.swift

@@ -18,7 +18,8 @@ extension ShellOutTests {
         ("testSeriesOfCommandsAtPath", testSeriesOfCommandsAtPath),
         ("testThrowingError", testThrowingError),
         ("testGitCommands", testGitCommands),
-        ("testSwiftPackageManagerCommands", testSwiftPackageManagerCommands)
+        ("testSwiftPackageManagerCommands", testSwiftPackageManagerCommands),
+        ("testZshShellCommands", testZshShellCommands)
     ]
 }
 #endif

Tests/ShellOutTests/ShellOutTests.swift

@@ -174,4 +174,24 @@ class ShellOutTests: XCTestCase {
         try shellOut(to: .generateSwiftPackageXcodeProject(), at: packagePath)
         XCTAssertTrue(try shellOut(to: "ls -a", at: packagePath).contains("SwiftPackageManagerTest.xcodeproj"))
     }
+
+    func testZshShellCommands() throws {
+        // Check current shell type
+        let bashNameEcho = try shellOut(to: "echo $0")
+        XCTAssertEqual(bashNameEcho, "/bin/bash")
+
+        let zshNameEcho = try shellOut(to: "echo $0", shellType: .zshPath)
+        XCTAssertEqual(zshNameEcho, "/bin/zsh")
+
+        // Test with arguments
+        let echo = try shellOut(to: "echo", arguments: ["Hello world"], shellType: .zshPath)
+        XCTAssertEqual(echo, "Hello world")
+
+        // Test with single command at path
+        try shellOut(to: "echo \"Hello\" > \(NSTemporaryDirectory())ShellOutTests-SingleCommand.txt", shellType: .zshPath)
+        let textFileContent = try shellOut(to: "cat ShellOutTests-SingleCommand.txt",
+                                           at: NSTemporaryDirectory(), shellType: .zshPath)
+
+        XCTAssertEqual(textFileContent, "Hello")
+    }
 }