Rsync error 13 permission denied
Sometimes when using `su` to run a script that runs `rsync` you will get an error like this:
rsync: pop_dir "/home/svn" failed: Permission denied (13) rsync error: errors selecting input/output files, dirs (code 3) at flist.c(1222)
In my case I was starting a script as root and the script was using `su` to change the user to "svn".
su svn -c "/home/svn/RSYNC_SVN.sh"
The fix was simply to tell `su` to use the user's environment. Note the dash after `su`:
su - svn -c "/home/svn/RSYNC_SVN.sh"