ditto - macOS

Overview

The ditto command in macOS is a versatile utility used for copying files and directories while preserving filesystem metadata and attributes. Commonly utilized in backup processes, software development, and system restoration tasks, ditto can create exact replicas of the source structure, ensuring permissions and resource forks are maintained.

Syntax

The basic syntax of the ditto command is:

ditto [options] source destination

Where:

  • source specifies the source file or directory.
  • destination specifies the destination file or directory where the contents will be copied.

Options/Flags

A variety of options are available with ditto that control its behavior:

  • -V, --verbose: Outputs a line for each item being processed, providing a detailed operation view.
  • -c: Creates a PKZip archive instead of copying files.
  • -x: Specifies that the source archive should be unzipped if used with -c.
  • -k: Use PKZip/ZIP format instead of CPIO when creating archives.
  • --password PASSWORD: Encrypts zip files with a password. Beware that this is less secure as the command-line password might be visible.
  • --nopreserveHFSCompression: Avoids preserving HFS compression data, which can be relevant for performance.
  • -cP: Copies ACLs (Access Control Lists) and preserves timestamps.
  • --sequesterRsrc: Keeps resource forks and Finder metadata in AppleDouble files on non-HFS volumes.
  • --keepParent: Preserves the parent directory structure of the source.
  • --noqtn: Does not copy Finder metadata or resource forks.

Examples

  1. Basic Copying:
    Copy a directory from source to destination, preserving all metadata:

    ditto /path/to/source /path/to/destination

  2. Verbose Output:
    Copy files while listing each file processed:

    ditto -V /path/to/source /path/to/destination

  3. Creating a Zip Archive:
    Archive an entire directory into a zip file:

    ditto -c -k --sequesterRsrc /path/to/source /path/to/destination.zip

  4. Unzipping a File:
    Extract a zip file to a specified directory:

    ditto -x -k /path/to/source.zip /path/to/destination

Common Issues

  • Permissions Error:
    Ensure you have the necessary permissions to access both source and destination, otherwise, ditto will fail.
  • Resource Fork Issues:
    When moving files to non-MAC OS filesystems, consider using --sequesterRsrc to maintain resource forks and metadata.

Integration

ditto can be combined with other commands for scheduled backups or complex scripts. For example, using cron to schedule backup operations:

0 1 * * * /usr/bin/ditto /home/user/docs /backups/docs_backup

This cron job runs ditto every day at 1:00 AM to backup docs directory.

  • cp: Standard Unix command to copy files and directories.
  • rsync: Another powerful tool for copying files that supports remote sources.
  • tar: Used for creating archives and backing up.

For more details on using ditto and related concepts, consult the official macOS documentation: