If you are logged in to your Blogger account, you can easily download a dump of your website by clicking on the Settings  Other  Export Blog link. (Source.)How can I do this automatically each day on Linux, from a cron job?
How can I programmatically back up my Blogger site?
blogger;backup
First you need to do a login with curl and then you can simply invoke another call to the download link. I would follow this article to accomplish this. The trick is to find out which URL you need to call to export your blog. What I did is: Use ChromeOpen developer tools (F12 or ctrl+shift+j).Select the network tab. Go to the export button/link and click it.You will see the download happening, and you will see a new record in the network tab. Mine is : http://draft.blogger.com/feeds/7135654868651822450/archive (if not authenticated you will get 404). (update by Mark Harrison) Based on the information above, here is a script that will download the xml dump of the blog. (end update)FEED=12312312312312313GMAIL=yourname@gmail.comecho -n google passwd:stty -echoread GPASSstty echo                  AUTH=`curl 2>/dev/null https://www.google.com/accounts/ClientLogin \    -d Email=$GMAIL \       -d Passwd=$GPASS  \    -d accountType=GOOGLE \    -d source=blogix \    -d service=blogger \  | grep '^Auth=' | cut -c 6-`curl >blog.xml \    -H Authorization: GoogleLogin auth=$AUTH \    http://www.blogger.com/feeds/$FEED/archive