The `-a` switch to `rsync` causes it to copy extra information that may be
incompatible with the destination if it uses a non-native filesystem (such as
FAT or NTFS). Since most of this additional information is not necessary in a
backup and can cause copy errors, it should be excluded by default. Instead,
the `-r` flag is used to enable recursive copies, and the `-t` flag to
preserve file timestamps.
If not specified, a file named `backups.ini` in the directory specified by the
`XDG_CONFIG_DIR` environment variable (or `~/.config` if it is not set).
To ensure that output is generated, even when no errors occur, and thus cron
sends an email message, we'll print some informational messages before and
after running the backup. These can be switched off with the `-q`/`--quiet`
argument.
Dustin C. Hatch