In other words alternative implementations of this:
ruby -pi -e "gsub(/Net::HTTPServerException/, 'Net::HTTPClientException')" {lib,knife}/**/*.rb
Some languages also have nice tools for this, such as gofmt -r; I don't know if something like that exists for Ruby.
perl -pi -e 's/from/to/g' list_of_files
In other words alternative implementations of this: