Scripting Swift

How to use Swift as shell script language.

Swift not only allows you to write compiled applications with or without UI interaction, but also is able to be run as command line shell scripts.

Simply start a new Swift file by adding the usual #! … front matter as the first line of your source code and add the path to the location of the swiftc command — and you're set. Here is a practical example:

#!/usr/bin/swift

/*
 Some nice formatting while printing to the console. We use ANSI TTY escape sequences and colour codes here. `CustomStringConvertible` makes the handling of the struct much easier.
 */
enum Colour: String, CustomStringConvertible {
	var description: String {
		self.rawValue
	}

	case reset = "\u{1b}[0m"
	case colourReset = "\u{1b}[39;49m"
	case bold = "\u{1b}[1m"
	case red = "\u{1b}[37;41m"
	case green = "\u{1b}[37;42m"
	case blue = "\u{1b}[37;44m"
}

print("\(Colour.blue)\(Colour.bold) Hello, \(Colour.red) Swift! \(Colour.reset)")

Save the file as — for example — hello_swift.swift and make it executable by setting the corresponding flag:

chmod u+x hello_swift.swift

You then can execute the Swift script by dotting it like so:

./hello_swift.swift

Please find my Swift scripts in the corresponding GitHub repository.