Is there a simple command to convert a branch to a tag?

Question

I am about to complete a tedious process of converting \"dumb snapshots\" to git. This process has been going very well (thanks to this rename process), but now I realized that

Answer 1

The answers given are basically correct.

As tags and branches are just names for objects, there is a simpler way without touching current work area:

git tag  refs/heads/ # or just git tag  
git branch -d 

Or even do it to remote server without touching local repository at all:

git push origin origin/:refs/tags/
git push origin :refs/heads/