At the end of each document, I'd like to include my signature but don't want to have to change every document I wrote when my home document moves. So, I can use a server include tag to include it, like this:
Note:
Having the server parse documents is a double edged sword. It can be costly
for heavily loaded servers to perform parsing of files while sending them.
Further, it can be considered a security risk to have average users executing
commands as the server's User.
If you disable the exec option, this danger is mitigated, but the performance
issue remains. You should consider these items carefully before activating
server-side includes on your server.