Terminal test command is not working as expected in Swift - swift

Question

When I run following shell command either on terminal or as a shell script:
test -f test.dmg && rm test.dmg
Output: It deletes test.dmg, if presents in the current directory.
However, while running the same command in swift as below, its not working as expected:
#!/usr/bin/env xcrun swift
func shell(launchPath: String, arguments: [AnyObject] = []) -> String? {
let task = NSTask()
task.launchPath = launchPath
task.arguments = (arguments as! [String])
print(task.arguments)
let pipe = NSPipe()
task.standardOutput = pipe
task.launch()
let data = pipe.fileHandleForReading.readDataToEndOfFile()
let output = NSString(data: data, encoding: NSUTF8StringEncoding)
print(output)
return (output as! String)
}
let arguments = ["test", "-f", "test.dmg", "&&", "rm", "test.dmg"]
shell("/bin/sh", arguments)
Output with swift: test: test: is a directory
Can somebody help with this?

Answer 1

You have two problems here.
The reason for the error is because you have a test directory in the current directory and (because of the second error) the shell is trying to execute it as a script and failing.
The second error is that you don't pass commands to the shell to run directly as independent arguments.
That is you don't do this:
/bin/sh test -f test.dmg && rm test.dmg
What you do is you use the -c flag to the shell and pass the entire command as a single string to it:
/bin/sh -c 'test -f test.dmg && rm test.dmg'
Which would make your code something like this:
let arguments = ["-c" "test -f test.dmg && rm test.dmg"]
shell("/bin/sh", arguments)