Migrate from another tool

Moving to dotsync always takes the same three steps: make sure the real files are in place on one machine, dotsync add them there, then dotsync init every other machine. Use a new, empty repository for dotsync: its layout (manifest.json plus files/) is its own.

Your dotfiles are symlinks into a directory like ~/dotfiles. dotsync follows a symlinked target as long as the file it points to is inside your home directory, so you can start straight away. For a clean result that no longer depends on the old directory, replace the links with real files first:

Turn each link into a regular file:

# Linux (GNU coreutils)
for f in ~/.gitconfig ~/.zshrc; do cp --remove-destination "$(readlink -f "$f")" "$f"; done
# macOS
for f in ~/.gitconfig ~/.zshrc; do src=$(readlink "$f"); rm "$f"; cp "$src" "$f"; done

For a linked directory, stow -D <package> removes the links; then copy the package’s files into place.

dotsync init <new-url>, and dotsync add the real paths.
On every other machine, run stow -D for the migrated packages, then dotsync init <new-url>.

Your home directory is a git work tree, managed by yadm or by git --git-dir=$HOME/.cfg --work-tree=$HOME. The files are already real files in place.

On one machine, dotsync init <new-url> and dotsync add each file or directory you want managed.
On every other machine, dotsync init <new-url>.
Once dotsync status shows ok everywhere, retire the old setup: stop running yadm or your alias, and delete its repository (~/.local/share/yadm/repo.git for yadm, ~/.cfg for the bare-repository method). Your files stay where they are.

chezmoi renders files from a source directory into place, so the real files already exist.

On one machine, run chezmoi apply so the files are current, then dotsync init <new-url> and dotsync add them.
Templated files render differently on each machine. Either pick one rendering and move the per-machine parts into local include files, or keep those files under chezmoi.
On every other machine, dotsync init <new-url>, then run chezmoi forget on the migrated files so the two tools never manage the same file.

Mackup copies files to and from a folder in your cloud storage (mackup backup, mackup restore), or, in its older link mode, moves them there and links them back.

Make sure your files are real files in place. In copy mode they already are; run mackup restore if this machine is behind. In link mode, mackup link uninstall copies the files back and removes the links.
dotsync init <new-url>, and dotsync add the files you want.
On every other machine, do the same as step 1, then dotsync init <new-url>, and stop running Mackup for the migrated files.

After migrating, run dotsync status on each machine: every entry should be ok.