> ## Documentation Index > Fetch the complete documentation index at: https://docs.simular.ai/llms.txt > Use this file to discover all available pages before exploring further. # File > A file on a []'s filesystem. A file on a \[`Machine`]'s filesystem. Obtain via \[`Machine.file`]. The handle stays bound to the machine it came from: paths are meaningful only on that machine, and all operations run there. Content access is text-oriented (\[`File.read`] trims, \[`File.write`] takes strings). ## Constructor ```typescript File(): File ``` ### Returns `File` ## Methods ### copyTo() ```typescript copyTo(dest: string): File ``` Copies the file to `dest` on the same machine, returning a handle to the copy. Fails when `dest` already exists. Local: an absolute `dest` is used as-is. A relative `dest` is joined to the `SimularFiles` root (`..` is kept — this is a default base, not a sandbox). Android: `dest` must be absolute. #### Parameters #### Returns `File` ### delete() ```typescript delete(): void ``` Deletes the file, invalidating the handle. ### extension() ```typescript extension(): null | string ``` The file extension, if any. #### Returns `null | string` ### isReadonly() ```typescript isReadonly(): boolean ``` Whether the file is read-only. #### Returns `boolean` ### modified() ```typescript modified(): number ``` The last modification time as milliseconds since the Unix epoch. #### Returns `number` ### moveTo() ```typescript moveTo(dest: string): void ``` Moves the file to `dest` on the same machine. Fails when `dest` already exists. Path resolution as in \[`File.copyTo`]. #### Parameters ### name() ```typescript name(): string ``` The file name (last component of the path). #### Returns `string` ### path() ```typescript path(): string ``` The file's path on its machine, as a string. #### Returns `string` ### read() ```typescript read(): string ``` Reads the file and returns its trimmed contents. #### Returns `string` ### rename() ```typescript rename(newName: string): void ``` Renames the file in place (same parent directory). `newName` must be a single filename component. #### Parameters ### size() ```typescript size(): number ``` The file size in bytes. #### Returns `number` ### write() ```typescript write(content: string, append: boolean): void ``` Writes content to the file, overwriting it — or appending, with a newline inserted first when the file already has content. Parent directories are created if needed. #### Parameters