CSS Transition – 3d rotation

CSS:

.wrapper {
    position: relative;
}

.wrapper div {
    position: absolute;
    left: 0;
    top: 0;
    color: #fff;

    -webkit-transform-style: preserve-3d;
    -webkit-backface-visibility: hidden;
}

.front {
    background-color: red;
    z-index: 2;

    transition: all .4s ease-in-out;
    -webkit-transition: all .4s ease-in-out;
    -moz-transition: all .4s ease-in-out;
    -o-transition: all .4s ease-in-out;
}

.wrapper:hover .front {
    z-index: 2;
    -webkit-transform: rotateY(180deg);
}

.back {
    background-color: blue;
    z-index: 1;

    -webkit-transform: rotateY(-180deg);

    transition: all .4s ease-in-out;
    -webkit-transition: all .4s ease-in-out;
    -moz-transition: all .4s ease-in-out;
    -o-transition: all .4s ease-in-out;
}

.wrapper:hover .back {
    z-index: 3;
    -webkit-transform: rotateY(0deg);
}

HTML:

<div class="wrapper">
    <div class="front">FRONT</div>
    <div class="back">BACK</div>
</div>

Keep SSH session alive without sudo

vim ~/.ssh/config

# this example keep the session alive for 60sec x 480 = 8hours
ServerAliveInterval 60 #seconds
ServerAliveCountMax 480 #times of keep-alive signals to send

SSH without password, and key only login

# create rsa key, skip if already done
local> ssh-keygen -t rsa

# create .ssh/ in home
local> ssh USER@REMOTEHOST mkdir ~/.ssh

# cat local public key, pipe over to ssh, take the piped local key append into remote ~/.ssh/authorized_keys
local> cat ~/.ssh/id_rsa.pub | ssh USER@REMOTEHOST 'cat >> ~/.ssh/authorized_keys'

# now on remote
remote> sudo vim /etc/ssh/sshd_config
# add the following
PermitRootLogin no # disable ssh as root
PubkeyAuthentication yes # use key authentication
PasswordAuthentication no # disable password authentication