/**
 * Safe file system operations.
 * - Atomic writes (write to temp, then rename) with symlink protection
 * - Symlink detection
 * - Safe copy with optional backup
 */
/**
 * Check if a path is a symlink.
 */
export declare function isSymlink(filePath: string): Promise<boolean>;
/**
 * Check if a file exists (follows symlinks).
 */
export declare function fileExists(filePath: string): Promise<boolean>;
/**
 * Check if a file exists and is NOT a symlink.
 * Use this for security-critical paths where symlink following is dangerous.
 */
export declare function fileExistsStrict(filePath: string): Promise<boolean>;
/**
 * Check if a directory exists.
 */
export declare function dirExists(dirPath: string): Promise<boolean>;
/**
 * Get file size in bytes. Returns 0 if file doesn't exist.
 */
export declare function getFileSize(filePath: string): Promise<number>;
/**
 * Get file modification time. Returns null if file doesn't exist.
 */
export declare function getFileMtime(filePath: string): Promise<Date | null>;
/**
 * Ensure a directory exists, creating it recursively if needed.
 * Rejects symlinks for security.
 */
export declare function ensureDir(dirPath: string): Promise<void>;
/**
 * Atomically write content to a file.
 * Writes to a temp file in the same directory, then renames.
 * This prevents partial writes / corruption.
 * Rejects if the target path is a symlink (prevents symlink attacks).
 */
export declare function atomicWrite(filePath: string, content: string): Promise<void>;
/**
 * Read a file's contents. Returns null if file doesn't exist.
 */
export declare function readFileSafe(filePath: string): Promise<string | null>;
/**
 * Copy a file with an optional backup of the destination.
 * Rejects symlinks at both source and destination for security.
 */
export declare function safeCopy(source: string, destination: string, options?: {
    backup?: boolean;
    backupDir?: string;
}): Promise<void>;
/**
 * Remove a file if it exists.
 */
export declare function removeFile(filePath: string): Promise<boolean>;
/**
 * List files in a directory matching an optional extension filter.
 */
export declare function listFiles(dirPath: string, extension?: string): Promise<string[]>;