根據搜索到的資料，找到了這裏:

luo[~]ssh luo@192.168.100.233
Press ^@ (C-Space) to enter file transfer mode, then ? for help

luo@192.168.100.233‘s password: 
Welcome to Linux Mint 18.3 Sylvia (GNU/Linux 4.13.0-36-generic x86_64)

 * Documentation:  https://www.linuxmint.com
Last login: Sat Mar  3 14:09:53 2018 from 192.168
 
.100.233
luo[~]tail /etc/update-motd.d/00-header 
#    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

[ -r /etc/lsb-release ] && . /etc/lsb-release

if [ -z "$DISTRIB_DESCRIPTION" ] && [ -x /usr/bin/lsb_release ]; then
    # Fall back to using the very slow lsb_release utility
    DISTRIB_DESCRIPTION=$(lsb_release -s -d)
fi
 


printf "Welcome to %s (%s %s %s)\n" "$DISTRIB_DESCRIPTION" "$(uname -o)" "$(uname -r)" "$(uname -m)"
luo[~]cat /etc/lsb-release 
DISTRIB_ID=LinuxMint
DISTRIB_RELEASE=18.3
DISTRIB_CODENAME=sylvia
DISTRIB_DESCRIPTION="Linux Mint 18.3 Sylvia"

隨後，又對 motd 進行了進一步了解。發現，ubuntu 下執行 motd 的其實是一個叫 updatemotd 的框架，也就是實際打印上面內容的地方。

比如：https://wiki.ubuntu.com/UpdateMotd

版本不一樣，動作也有區別，但是，基本就是 motd 的範疇就對了。

ubuntu 登陸信息打印 -- motd