Swiftpack.co - Package - JohnSundell/ShellOut

🐚 ShellOut

Welcome to ShellOut, a simple package that enables you to easily “shell out” from a Swift script or command line tool.

Even though you can accomplish most of the tasks you need to do in native Swift code, sometimes you need to invoke the power of the command line from a script or tool - and this is exactly what ShellOut makes so simple.


Just call shellOut(), and specify what command you want to run, along with any arguments you want to pass:

let output = try shellOut(to: "echo", arguments: ["Hello world"])
print(output) // Hello world

You can also easily run a series of commands at once, optionally at a given path:

try shellOut(to: ["mkdir NewFolder", "echo \"Hello again\" > NewFolder/File"], at: "~/CurrentFolder")
let output = try shellOut(to: "cat File", at: "~/CurrentFolder/NewFolder")
print(output) // Hello again

In case of an error, ShellOut will automatically read STDERR and format it nicely into a typed Swift error:

do {
    try shellOut(to: "totally-invalid")
} catch {
    let error = error as! ShellOutError
    print(error.message) // Prints STDERR
    print(error.output) // Prints STDOUT

Pre-defined commands

Another way to use ShellOut is by executing pre-defined commands, that enable you to easily perform common tasks without having to construct commands using strings. It also ships with a set of such pre-defined commands for common tasks, such as using Git, manipulating the file system and using tools like Marathon, CocoaPods and fastlane.

Use Git

try shellOut(to: .gitInit())
try shellOut(to: .gitClone(url: repositoryURL))
try shellOut(to: .gitCommit(message: "A scripted commit!"))
try shellOut(to: .gitPush())
try shellOut(to: .gitPull(remote: "origin", branch: "release"))
try shellOut(to: .gitSubmoduleUpdate())
try shellOut(to: .gitCheckout(branch: "my-feature"))

Handle files, folders and symlinks

try shellOut(to: .createFolder(named: "folder"))
try shellOut(to: .createFile(named: "file", contents: "Hello world"))
try shellOut(to: .moveFile(from: "path/a", to: "path/b"))
try shellOut(to: .copyFile(from: "path/a", to: "path/b"))
try shellOut(to: .openFile(at: "Project.xcodeproj"))
try shellOut(to: .readFile(at: "Podfile"))
try shellOut(to: .removeFile(from: "path/a"))
try shellOut(to: .createSymlink(to: "target", at: "link"))
try shellOut(to: .expandSymlink(at: "link"))

For a more powerful and object-oriented way to handle Files & Folders in Swift, check out Files

Use Marathon

try shellOut(to: .runMarathonScript(at: "~/scripts/MyScript", arguments: ["One", "Two"]))
try shellOut(to: .updateMarathonPackages())

Use The Swift Package Manager

try shellOut(to: .createSwiftPackage(withType: .executable))
try shellOut(to: .updateSwiftPackages())
try shellOut(to: .generateSwiftPackageXcodeProject())
try shellOut(to: .buildSwiftPackage())
try shellOut(to: .testSwiftPackage())

Use fastlane

try shellOut(to: .runFastlane(usingLane: "appstore"))

Use CocoaPods

try shellOut(to: .updateCocoaPods())
try shellOut(to: .installCocoaPods())

Don't see what you're looking for in the list above? You can easily define your own commands using ShellOutCommand. If you've made a command you think should be included among the built-in ones, feel free to open a PR!


For scripts

  • Install Marathon.
  • Add ShellOut to Marathon using $ marathon add https://github.com/JohnSundell/ShellOut.git.
  • Alternatively, add https://github.com/JohnSundell/ShellOut.git to your Marathonfile.
  • Write your script, then run it using $ marathon run yourScript.swift.

For command line tools

  • Add .package(url: "https://github.com/JohnSundell/ShellOut.git", from: "2.0.0") to your Package.swift file's dependencies.
  • Update your packages using $ swift package update.

Help, feedback or suggestions?

  • Open an issue if you need help, if you found a bug, or if you want to discuss a feature request.
  • Open a PR if you want to make some change to ShellOut.
  • Contact @johnsundell on Twitter for discussions, news & announcements about ShellOut & other projects.


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2.2.1 - Dec 12, 2019

  • A race condition that could occur when capturing output data is now being avoided (by @helje5)
  • ShellOut no longer closes standard file handles (like stdin and stderr) when finishing (by @SteveBarnegren)

2.2.0 - Dec 30, 2018

This version migrates ShellOut to Swift 4.2

2.1.0 - Jan 4, 2018

ShellOut is now thread safe thanks to @harlanhaskins 🎉

2.0.0 - Nov 5, 2017

  • ShellOut now uses Swift 4.
  • copyFile and removeFile has been added to the convenience API.
  • You can now use paths containing a tilde to refer to the home folder.
  • More user friendly descriptions of errors.

1.2.1 - Aug 28, 2017

This release fixes build errors on Linux, since attaching handlers to FileHandles is not yet supported in the Swift standard library on that platform.