tags_db is an extremely simple bash script that lets you add a value and associate tags with it. It is backed by sqlite3. I am using it as my own personal version of the delicious webapp.
There is a script to import a delcious export to tags_db.
Initialize a db
tags_db init
tags_db add name [tag1 tag2 ... tagn]
Print all names
tags_db all
tags_db tags_add name [tag1 tag2 ... tagn]
Print all tags in the system
tags_db tags_all
tags_db tags_del name [tag1 tag2 ... tagn]
Searches for the intersection of tags
tags_db tags_search [tag1 tag2 ... tagn]
Shows the tags associated with a name
tags_db tags_show name
Delete a name and its associated tags
tags_db del name