That will appear in plain text in your terminal history file. And, if you are on a multi-user machine, even non-privileged users will be able to see your command line.
You should never put any password or private key on a command line (any command line, not just in your terminal). Instead, use the unix-standard getpass function or it's equivalent in your language/library of choice.
you can just run md5 alone and pass the "qwerty http://www.facebook.com<Enter><Ctrl-D> at its stdin. And its less to type too (Thats Ctrl-D at the end is to signal end of stream)
You should never put any password or private key on a command line (any command line, not just in your terminal). Instead, use the unix-standard getpass function or it's equivalent in your language/library of choice.