Well, I've been using this "password manager" for quite a while now and decided to share with everyone.
sudo cat /home/you_user_name/your_password_file.txt | grep $1 | cut -d "|" -f1 | tr -d "\n" | xclip -selection clipboard
Where 'your_password_file.txt' is a text file (accessible by your user only, with your password) with the following pattern:
password|place_that_password_belongs_to
this way you can create all kinds of crazy passwords, like:
fAnPb;dL998Bm(~|google
\9prC82D#DW2(V!|facebook
zbKBq@76P]FJ<;{|hackernews
So when you call your script passing 'google' as an argument, it will place your crazy password into your copy/paste.