PrefixFiles.swift

#!/usr/bin/swift

import Foundation

let Usage = "Usage: PrefixFiles.swift <directory> <prefix>"

extension String: ErrorType {}

extension NSURL {
    
    var fileName: String? {
        
        return self.URLByDeletingPathExtension?.lastPathComponent ?? self.lastPathComponent
    }
    
    func URLByRenamingFileName(name: String, ext: String? = nil) -> NSURL? {
        
        let baseURL = self.URLByDeletingLastPathComponent
        
        var result = baseURL?.URLByAppendingPathComponent(name)
        
        if let ext = ext ?? self.pathExtension  {
            
            result = result?.URLByAppendingPathExtension(ext)
        }
        
        return result
    }
}

do {
    
    guard Process.arguments.count > 2 else {
        
        throw Usage
    }
    
    let path = Process.arguments[1]
    let dir = NSURL(fileURLWithPath: path)
    let prefix = Process.arguments[2]
    
    var files = try NSFileManager.defaultManager().contentsOfDirectoryAtURL(dir, includingPropertiesForKeys: nil, options: [.SkipsHiddenFiles, .SkipsPackageDescendants, .SkipsSubdirectoryDescendants])
    
    try files.forEach({ (file) in
        
        //prefix all files
        let fileName = file.fileName!
        let newName = prefix + fileName
        
        let renamedFile = file.URLByRenamingFileName(newName)!
        
        try NSFileManager.defaultManager().moveItemAtURL(file, toURL: renamedFile)
    })
}
catch let e {
    
    print(e)
}