My copy of git-annex refuses to sync all, namely when I try it I get the following error

$ git annex sync --content --all
git-annex: unrecognized option `--all'

Usage: git-annex sync [REMOTE ...] [option ...]
    --content  also transfer file contents

To see additional options common to all commands, run: git annex help options

This contradicts the advice on preferred content set out under difference: unused, and I cannot see any other options in my man page that would address the lack of this option.

The problem I am trying to solve is that I wish to preserve all history on the backup drives. Namely, if I do the following

touch test-of-annex-backup.txt
git annex add test-of-annex-backup.txt
git commit --message='test: Create empty test-of-annex-backup.txt file'
git annex edit test-of-annex-backup.txt
echo "This line creates version 2 of this file" > test-of-annex-backup.txt
git annex add test-of-annex-backup.txt
git commit --message='test: Create version 2 of test-of-annex-backup.txt'
git annex sync --content --all

I expect to see 2 copies of test-of-annex-backup.txt be copied to each accessible annex repository in the backup group

I tried googling for "git annex sync --content --all", but I only find pages telling me that this is what I should use, and none saying the option has been deprecated.

I am very confused, as this seems to me an almost stereotypical use of git-annex, and yet I cannot see how to do it

thanks

Andrew