The `file` module provides access to the local filesystem. Paths ----- Path specifications in this API are platform-specific. This means that on Windows paths are specified using the backslash path separator (`\`), and on Unix-like systems like Linux and OS X paths are specified using the forward slash path separator (`/`). If your add-on uses literal Windows-style path specifications with this API, your add-on likely won't work when users run it on Unix-like systems. Likewise, if your add-on uses literal Unix-style path specifications, it won't work for users on Windows. To ensure your add-on works for everyone, generate paths using the [`join`](modules/sdk/io/file.html#join(...)) function. Unfortunately this API does not currently provide a way to obtain an absolute base path which you could then use with `join`. For now, you need to [`require("chrome")`](dev-guide/tutorials/chrome.html) and use the XPCOM directory service as described at [MDN](https://developer.mozilla.org/en/Code_snippets/File_I%2F%2FO#Getting_special_files). Note that if you do decide to hardcode Windows-style paths, be sure to escape backslashes in strings. For example, to specify the file at `C:\Users\Myk`, you need to use the string `"C:\\Users\\Myk"`, not `"C:\Users\Myk"`. You can read more about escaping characters in strings at [MDN](https://developer.mozilla.org/en/JavaScript/Guide/Values,_Variables,_and_Literals#Escaping_Characters). @function Returns the last component of the given path. For example, `basename("/foo/bar/baz")` returns `"baz"`. If the path has no components, the empty string is returned. @param path {string} The path of a file. @returns {string} The last component of the given path. @function Returns the path of the directory containing the given file. If the file is at the top of the volume, the empty string is returned. @param path {string} The path of a file. @returns {string} The path of the directory containing the file. @function Returns true if a file exists at the given path and false otherwise. @param path {string} The path of a file. @returns {boolean} True if the file exists and false otherwise. @function Takes a variable number of strings, joins them on the file system's path separator, and returns the result. @param ... {strings} A variable number of strings to join. The first string must be an absolute path. @returns {string} A single string formed by joining the strings on the file system's path separator. @function Returns an array of file names in the given directory. @param path {string} The path of the directory. @returns {array} An array of file names. Each is a basename, not a full path. @function Makes a new directory named by the given path. Any subdirectories that do not exist are also created. `mkpath` can be called multiple times on the same path. @param path {string} The path to create. @function Returns a stream providing access to the contents of a file. @param path {string} The path of the file to open. @param [mode] {string} An optional string, each character of which describes a characteristic of the returned stream. If the string contains `"r"`, the file is opened in read-only mode. `"w"` opens the file in write-only mode. `"b"` opens the file in binary mode. If `"b"` is not present, the file is opened in text mode, and its contents are assumed to be UTF-8. If *`mode`* is not given, `"r"` is assumed, and the file is opened in read-only text mode. @returns {stream} If the file is opened in text read-only `mode`, a `TextReader` is returned, and if text write-only mode, a `TextWriter` is returned. See [`text-streams`](modules/sdk/io/text-streams.html) for information on these text stream objects. If the file is opened in binary read-only `mode`, a `ByteReader` is returned, and if binary write-only mode, a `ByteWriter` is returned. See [`byte-streams`](modules/sdk/io/byte-streams.html) for more information on these byte stream objects. Opened files should always be closed after use by calling `close` on the returned stream. @function Opens a file and returns a string containing its entire contents. @param path {string} The path of the file to read. @param [mode] {string} An optional string, each character of which describes a characteristic of the returned stream. If the string contains `"b"`, the contents will be returned in binary mode. If `"b"` is not present or `mode` is not given, the file contents will be returned in text mode. @returns {string} A string containing the file's entire contents. @function Removes a file from the file system. To remove directories, use `rmdir`. @param path {string} The path of the file to remove. @function Removes a directory from the file system. If the directory is not empty, an exception is thrown. @param path {string} The path of the directory to remove.