Created:        2025-10-25 Sat
Last modified:  2025-10-25 Sat

Text-Based Copying of Directory Data: Tar and Base64

Data can be transferred between machines without traditional file transfer protocols. By using tar for packing and compression, and base64 for encoding, you can transfer directories via the clipboard.

Steps

  1. Pack, Compress and Encode:

    • Navigate to the parent directory of the directory you wish to copy and run:

      tar -cz <source_directory> | base64

    • Copy the resulting base64 string to your clipboard.


  1. Decode and Extract:

    • On the destination machine, save the base64 string from the clipboard into a file and execute:

      base64 -d <base64_string_file> | tar -xzf -

Verbose Output with the -v Flag

Adding the -v flag to the tar command prints the filenames as they are being processed. This provides more insight into which files are included in the operation.

Filtering Files by Size

For directories containing large files you wish to exclude, you can filter them out during packing. The example below excludes files larger than 1MB:

find <source_directory> -type f -size -1M -print0 | tar --null -czf - --files-from=- | base64

Checking Output Size

To check the size of the base64 encoded output, you can use the wc -c command, which counts the total number of bytes:

tar -cz <source_directory> | base64 | wc -c

Notes

  1. This method is suited for small data sizes due to clipboard buffer limitations.

  2. More space-efficient encodings exist, such as base85, which reduces overhead to about 25% compared to the 33% overhead of base64. However, base85 (ascii85) is not commonly preinstalled.

  3. Compression options for the tar command are not limited to -z; you can also use -j for bzip2 or -J for xz. If desired, compression can be skipped altogether by omitting the compression flag.