Remove trailing whitespace, convert tabs to spaces and file format to unix (remove ugly ^M carriage returns) from files using a single command:
vim -es -c 'set et ts=2 | bufdo retab | %s/\s\+$//e | set ff=unix | w' -c 'q' FILES
vim -es -c 'set et ts=2 | bufdo retab | %s/\s\+$//e | set ff=unix | w' -c 'q' $(find scripts -name '*.sh' -type f)
If in doubt, ask man
.