Swift Cheatsheet - Swift & iOS Development Command Reference

This reference is for Swift developers shipping iOS/macOS apps, command-line tools, or server code, spanning the two toolchains you bounce between: the Swift/SwiftPM CLI and xcodebuild/xcrun simctl. It covers compiling and running scripts, initializing and building Swift packages, building/testing/archiving a scheme, driving simulators, and the syntax idioms (let/var, optional binding, map/filter/reduce) plus debug/assert helpers you reach for daily. Unlike a flat Swift command list, entries are grouped by the actual cycle of compile → test → archive → run on simulator. After reading, you should be able to take a package from swift package init to a passing swift test, and drive an Xcode scheme from the terminal.

Languages·34 commands·Last updated 2026-07-21

Compile & Run 6

swift main.swift

Run a Swift script

swiftc main.swift -o main

Compile to an executable

swift main.swiftc

Enter the REPL

swift -e "print("Hello")"

Run a one-liner

swift package init --type executable

Init an executable package

swift package init --type library

Init a library package

Swift Package Manager 8

swift build

Build the project

swift build -c release

Build in release mode

swift run

Build and run

swift test

Run tests

swift package resolve

Resolve dependencies

swift package update

Update dependencies

swift package reset

Reset package cache

swift package show-dependencies

Show dependency tree

Xcode CLI 7

xcodebuild -list

List project schemes

xcodebuild -scheme MyApp build

Build a given scheme

xcodebuild -scheme MyApp test

Run tests

xcodebuild archive -scheme MyApp

Archive the project

xcrun simctl list devices

List simulators

xcrun simctl boot <device-id>

Boot a simulator

xcrun simctl install booted MyApp.app

Install to a simulator

Common Syntax 8

var name: String = "Swift"

Mutable variable

let age: Int = 18

Constant

if let value = optional { ... }

Optional binding

guard let value = optional else { return }

Early exit (guard)

array.map { $0 * 2 }

Map

array.filter { $0 > 5 }

Filter

array.reduce(0) { $0 + $1 }

Reduce

for (index, value) in array.enumerated()

Enumerate with index

Debug & Performance 5

print("debug: \(variable)")

Print debug info

debugPrint(object)

Pretty-print (with type)

assert(condition, "message")

Assert (debug builds)

precondition(condition, "message")

Precondition (all builds)

Instruments

Instruments (Xcode profiler)

Tips

swift package init generates Package.swift, the SPM manifest.
Optionals are core to Swift safety; unwrap with if let / guard let.
xcodebuild CLI fits CI/CD automated builds and tests.

Official References

Each command links to its official documentation below, so you can verify the latest usage and read deeper.

Official Docs

Maintained by LaoHand

Publicly updated on Jul 21, 2026, continuously proofread against official docs.

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