ssh to a server without input long host name and password every time:

On your own linux system, run the following:

ssh-keygen -f xxx      //produce key file xxx  and xxx.pub. You can use a password to protect the key, or just leave password empty
ssh-copy-id -i xxx.pub username@server   // install the pub key to the server you want to log in.  After this command you should be able to find .ssh/authorized_keys on server
cp xxx to .ssh/

make .ssh/config file and add the following lines:

HOST lx         //simple name of the server
   HostName theServerName
   User Username
   IdentityFile ~/.ssh/xx

Now, you can log in with " ssh lx". and log in without password. previously you have to ssh username@server and input password