背景
希望每次ssh登录树莓派时欢迎信息可以显示系统状态
包括CPU温度与用量，内存和硬盘用量
代码
控制树莓派登录欢迎信息的文件有两处
- 位于
/etc/update-motd.d/目录下的shell脚本 - 上述脚本执行完毕后打印
/etc/motd文本
新建欢迎脚本
$ sudo vi /etc/update-motd.d/11-info
部分源自Adafruit的开源项目修改而来（已停止维护）
#!/bin/sh
uptime | awk '{printf("
CPU Load: %.2f ", $(NF-2))}'
free -m | awk 'NR==2{printf("Mem: %s/%sMB %.2f%%
", $3,$2,$3*100/$2)}'
cat /sys/class/thermal/thermal_zone0/temp|awk '{printf("CPU Temp: %.2f ",$1/1000)}'
df -h | awk '$NF=="/"{printf "Disk: %.1f/%.1fGB %s
", $3,$2,$5}'
添加执行权限
$ sudo chmod +x /etc/update-motd.d/11-info
取消原始静态欢迎信息（可选）
$ sudo mv /etc/motd /etc/motd.sample
效果
更换前
Linux rpi0w 4.19.57+ #1244 Thu Jul 4 18:42:50 BST 2019 armv6l
The programs included with the Debian GNU/Linux system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.
Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.
Last login: Thu Nov 26 19:57:02 2020 from 127.0.0.1
更换后
Linux rpi0w 4.19.57+ #1244 Thu Jul 4 18:42:50 BST 2019 armv6l
CPU Load: 0.01 Mem: 74/432MB 17.13%
CPU Temp: 29.86 Disk: 2.0/7.1GB 30%
Last login: Thu Nov 26 19:57:02 2020 from 127.0.0.1