function ssh-del-num {
    local line_no
    set -u
    line_no=${1}

    sed -i.bak "${line_no}d" ~/.ssh/known_hosts
    set +u
}

function ssh-del-name {
    local host_name
    set -u
    host_name=${1}
    sed -n "/${host_name}/p" ~/.ssh/known_hosts
    printf "Delete the above? (y/n)"
    read -q resp
    if [[ "y" == "${resp}" ]]; then
        sed -i.bak "/${host_name}/d" ~/.ssh/known_hosts
    fi

    set +u
}