Social bookmarking services like Delicious are great for sharing your bookmarks with others or just across multiple computers. But one disadvantage of having them stored in a central location is that you have no control over the backup strategy they use. What if they suffer from a system crash and lose all your data?
If you think I'm just being paranoid, think of what happened to Ma.gnolia recently.

Just to be safe, I wrote a simple little script that takes a copy of all my bookmarks - in XML format - and stores it locally on my PC. Because it is in XML format, converting this data to some other format in the future should be fairly trivial.

#!/bin/sh
 
# Your delicious username and password, separated by a colon
CREDENTIALS="UserName:YourPassword"
# Location where the backup will be stored
BACKUP_DIR="$HOME/backups/del.icio.us"
 
 
if [ ! -d "$BACKUP_DIR" ] ; then
  mkdir -p "$BACKUP_DIR"
fi
 
DATE=$(date +"%Y%m%d")
curl --user "$CREDENTIALS" -o "$BACKUP_DIR/bookmarks-$DATE.xml" -O "https://api.del.icio.us/v1/posts/all"

The script is run from cron on a regular basis, so even if something were to happen to Delicious, I still have a copy of all my bookmarks. Lets hope I never need it.