10 Tips to Run Swift From Your Terminal

‘swift’, ‘swiftc’, and ‘lldb’

Photo by Ilya Pavlov on Unsplash

Sometimes when writing a block of Swift code, I don't bother to launch Xcode. Running the Swift commands swift and swiftc from the terminal are more lightweight and convenient. To debug and set a breakpoint, lldb does the job.

1. ‘swift’ Command to Get the Swift Version

After installing the latest version of Swift from the download page, I’ll run the command to verify I’m running the expected Swift version:

$ swift --version

Swift version

• It shows I’m currently on Swift 5.3
• The Swift/Objective-C compiler is on version 12
• The Swift environment is MacOS Catalina on a 64 bit CPU

2. Swift Command to Run the Swift File

Let’s using the vi editor to write our first Swift file Foo.swift to print out “Hello world!”:

$ vi Foo.swift

Write down the foo() function, and execute it:

‘Foo.swift’

To run the file, we use:

$ swift Foo.swift

Run Swift file

3. Run the Swift File With Parameters

The CommandLine enumeration is part of the Swift standard library to provide the command line arguments. We use CommandLine.arguments to get the parameters after the swift command.

To print out the “Hello, Foo!” message, the code is:

‘Foo.swift’ with arguments

To run the file with arguments, we use:

$ swift Foo.swift Foo