How can I convert tabs to spaces in every file of a directory?

Question

How can I convert tabs to spaces in every file of a directory (possibly recursively)?

Also, is there a way of setting the number of spaces per tab?

Answer 1

Converting tabs to space in just in ".lua" files [tabs -> 2 spaces]

find . -iname "*.lua" -exec sed -i "s#\t#  #g" '{}' \;