export interface AtomicWriteOptions {
    /**
     * File permissions (octal number, e.g., 0o640).
     * Defaults to 0o640.
     */
    mode?: number;
    /**
     * File owner in "user" or "user:group" format.
     * Only applied when running as root.
     */
    owner?: string;
    /**
     * Force sync to disk before rename (fsync).
     * Recommended for critical data.
     * Defaults to false.
     */
    fsync?: boolean;
    /**
     * Create parent directories if they don't exist.
     * Defaults to true.
     */
    createDirs?: boolean;
    /**
     * Mode for created parent directories.
     * Defaults to 0o750.
     */
    dirMode?: number;
    /**
     * Create backup of existing file before write.
     * Backup will be at filePath + '.backup'.
     * Defaults to false.
     */
    backup?: boolean;
    /**
     * Verify written content by re-reading and comparing hash.
     * Defaults to false.
     */
    verify?: boolean;
}
/**
 * Write content to a file atomically.
 *
 * Uses temp file + rename pattern to ensure the file is either
 * fully written or not modified at all.
 *
 * @param filePath - Absolute path to target file
 * @param content - Content to write (string or Buffer)
 * @param options - Write options
 * @returns Hash of written content (SHA-256)
 */
export declare function writeAtomic(filePath: string, content: string | Buffer, options?: AtomicWriteOptions): string;
/**
 * Write content atomically with full durability guarantees.
 * This is the paranoid version with fsync, verification, and backup.
 *
 * @param filePath - Absolute path to target file
 * @param content - Content to write
 * @param options - Additional options
 * @returns Hash of written content
 */
export declare function writeAtomicDurable(filePath: string, content: string | Buffer, options?: Omit<AtomicWriteOptions, 'fsync' | 'verify' | 'backup'>): string;
/**
 * Calculate SHA-256 hash of content.
 *
 * @param content - Content to hash
 * @returns Hex-encoded hash
 */
export declare function hashContent(content: string | Buffer): string;
/**
 * Verify a file matches expected hash.
 *
 * @param filePath - Path to file
 * @param expectedHash - Expected SHA-256 hash
 * @returns true if file matches hash
 */
export declare function verifyFile(filePath: string, expectedHash: string): boolean;
/**
 * Recover file from backup if main file is corrupted or missing.
 *
 * @param filePath - Path to main file
 * @param validator - Optional function to validate content
 * @returns Recovered content or null
 */
export declare function recoverFromBackup(filePath: string, validator?: (content: string) => boolean): string | null;
/**
 * Clean up temp and backup files for a given path.
 *
 * @param filePath - Main file path
 */
export declare function cleanupTempFiles(filePath: string): void;
/**
 * Ensure a directory exists with proper permissions.
 *
 * @param dirPath - Directory path
 * @param mode - Directory mode (default: 0o750)
 * @param owner - Optional owner in "user:group" format
 */
export declare function ensureDir(dirPath: string, mode?: number, owner?: string): void;
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