What is the correct syntax to exclude directories whose first
character is '.', i.e. a dot?

A client admin is trying to exclude directories like /home/
username/.maildir from a Linux backup. The usual syntax, exclude.dir /
home/username/.maildir does not do this, and in my testing aborted
the preview program. Double-quotes around the path did not prevent
the abend, while double-quotes around the whole command string did
provoke a syntax error message.

The preview abend may be an ungraceful reaction to a syntax error in
the include/exclude file, but what is the correct syntax to exclude
directories whose first character is '.', i.e. a dot?

Thank you,
Keith Arbogast
Indiana University