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Executing commands in the Terminal from Swift

I’ve been working on a little MacOS app which is supposed to spawn a Terminal and execute commands in it. As I was digging through Process and NSTask I wasn’t able to find a way to do both of these actions. However through some embedded AppleScript, you can get it to work.

The below code will achieve exactly that:

func execute(command: String) {
    let script = """
tell application \"Terminal\"
    do script "\(command)"
end tell
    var error: NSDictionary?
    if let scriptObject = NSAppleScript(source: script) {
        let output = scriptObject.executeAndReturnError(&error)
        if (error != nil) {
            print("error: \(String(describing: error))")
        } else {
            print("output: \(String(describing: output.stringValue))")

If you now execute this, you’ll see an error similar to this in your console:

error: Optional({
    NSAppleScriptErrorAppName = Terminal;
    NSAppleScriptErrorBriefMessage = "Not authorized to send Apple events to Terminal.";
    NSAppleScriptErrorMessage = "Not authorized to send Apple events to Terminal.";
    NSAppleScriptErrorNumber = "-1743";
    NSAppleScriptErrorRange = "NSRange: {26, 55}";

In order to grant these permissions, add the following to your info.plist:

<string>hello jeroen</string>

If you now trigger this behaviour again, you’ll be prompted with the following popup:

Permission request for Terminal interaction

Note that this will only work if you don’t have Sandbox enabled. In order to disable the Sandbox, delete your .entitlements file.

Published 12 Jul 2020

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