Add character to the beginning of each line using sed Howto: Linux command line utilities for removing blank lines from text files How to remove XML tags from Unix command line? How to strip multipe spaces to one using sed?

http://www.cyberciti.biz/faq/create-ssh-config-file-on-linux-unix/ https://help.github.com/articles/working-with-ssh-key-passphrases/ http://www.thegeekstuff.com/2008/11/3-steps-to-perform-ssh-login-without-password-using-ssh-keygen-ssh-copy-id/