I want to write a bash script that will store 10 back ups of a website in SVN, with it being back up nightly and then have the oldest back up deleted.
Is there an SVN command where I can get the age of these files in svn so then I can grammatically call “svn delete” on that file?
Subversion is definitely not the tool for this job. Once you commit something to subversion, there is no practical way to delete it.
There are a lot of ways to achieve your goal using standard commands in bash. You can use tools like ftp, wget, curl, scp, ssh, or whatever to download your site files, then tar and zip them up with different file names based on the date.
Then just schedule this as a daily cron job.