Ubuntu 修改SSH欢迎文字

运行 man update-motd 命令获得描述信息

UNIX/Linux system adminstrators often communicate important information to console and remote users by maintaining text in the file /etc/motd, which is displayed by the
 pam_motd(8) module on interactive shell logins.
Traditionally, this file is static text, typically installed by the distribution and only updated on release upgrades, or overwritten by the local administrator with
 pertinent information.
Ubuntu introduced the update-motd framework, by which the motd(5) is dynamically assembled from a collection of scripts at login.
Executable scripts in /etc/update-motd.d/* are executed by pam_motd(8) as the root user at each login, and this information is concatenated in /var/run/motd. The order
 of script execution is determined by the run-parts(8) --lsbsysinit option (basically alphabetical order, with a few caveats).
On Ubuntu systems, /etc/motd is typically a symbolic link to /var/run/motd.

直接编辑vi /etc/motd文件加入内容,可以使用figlet工具生成图形字符