Q:

How can I get bash/zsh to change some text from "foo.foo.foo" to "foo foo foo" with a script/alias?

I can maybe use < or > or |. Maybe I need to use grep?

A:

You can use tr command to convert character.
% echo "foo.foo.foo" | tr '.' ' ' 
foo foo foo

A:

Using pure bash:
bash-3.2$ a='a.a.a'
bash-3.2$ echo "${a/./ }"
a a.a
bash-3.2$ echo "${a//./ }"
a a a

A:

You can make a function and add to the end of your ~/.bashrc, for example:
nodot() {  echo "$1" | sed 's/\./ /g' ; }

usage example:
$ nodot foo.foo.foo
foo foo foo

You can use this function in zsh too, just add to your ~/.zshrc instead.

