I was doing a MySQL dump over SSH using Putty, and now it is just typing PuTTY over and over again into the console, Ctrl+C doesn't do anything.
Does anyone know why this is happening?
Yes. Your mysql dump is not clear text, but contains terminal controlling characters as well. Practically, it contains binary data. You can experience the similar flash if you print any binary data into your screen, f.e.
It shouldn't happen so. Some solutions:
mysqldump ...|iconv -f your-actual-encoding-which-is-probably-utf-8 -t utf-7.
vimis very good in binary data editing. If your problem was caused by big blobs,
hexeditcan be also useful.