I’ve finally clued in to setting and using simple strings within Terminal. Set a string:

name='David DeSandro'

No spaces around the =. Quotes are required if your string has spaces. Reference it with $

echo $name
# will output `David DeSandro`

For example, when creating a new post, I have to reference the same long filename several times.

dropfile='_posts/2011/2011-04-12-terminal-strings.mdown'
mate $dropfile
git add $dropfile
tumblr $dropfile