Spaces (and other characters) in filenames

[Dotan Cohen]

I must come to a solution that will satisfy the wife's need of spaces
in filenames and linux's hate of the practice. Is there a simple
command that I can run that will convert all the spaces in filenames
in recursive directories (including the directories) to an underscore,
and another command that will recovert all the underscores to spaces?

I also need to know what characters are valid in filenames. I know
that [a-z][A-Z][0-9] are valid, but what about comma, single- and
double-quote, grerater- and lesser- than signs, etc? What is valid? Is
there a command that I can run that will convert all the invalid
characters in recursive directories to something valid, such as a
minus sign?

I know that I really do need to learn bash to answer these questions
on my own. I intend to do that, in the little spare time that I have,
but in the meantime I very much appreciate everybody's patience with
my ignorance. Computer major I am not!

Dotan Cohen
http://what-is-what.com