See also my little project fugitive [1] a blog engine running on top of git using hooks written in Bash (not much more than 500 lines either), well technically it's even written in bare sh.
And you would have been sooooooooo right. Since I wanted to use sh only and not even Bash, I don't even have some useful Bash features such as arrays, so I use temporary files for many many things. Plus invoking a git process for each meta information, plus an awefull lot of sed processes for the templating system… I have a few users with a growing number of blogposts who are complaining about the speed when regenerating their archives page and RSS feed. But now I don't feel like rewriting it in Perl. Plus I had a lot of fun coding in sh.
If you or anyone feels like writing a fugitive clone in Perl, I can assure you a few users as soon as its working!
[1] http://gitorious.org/fugitive