Maintain an encrypted lockbox of data, accessible only by you. Performs fast file-by-file encryption on every file in a directory recursively. This script should be capable of running in macOS or in Linux.
Right now, lockbox will smartly skip encrypting any files that aren't writable by the current user. To avoid a false sense of security, lockbox should present a list of the skipped files (before encryption) and ask the user to confirm. Maybe include a --force to skip the interactive check.
Right now, lockbox will skip encrypting any files that aren't writable, even if they're owned by the current user. Attempting recursive chmod +w before encrypting would maximize the files that could be encrypted.
However, this may not be what the user desires. Consider an argument to opt-in or opt-out? Or maybe an interactive question?