简单shell 编程

 1 #!/bin/bash
 2 while true
 3 do
 4     echo 
 5     clear
 6     echo 
 7     echo "        系统维护菜单        "
 8     echo "============================ "
 9     echo "      1)显示系统日期         "
10     echo "      2)修改系统日期         "
11     echo "      3)显示已登录用户       "
12     echo "      4)重启电脑             "
13     echo "      5)关机                 "
14     echo "      6)退出                 "
15     echo "============================ "
16     echo "                            "
17     echo -n "请选择："
18     read sel
19     case ${sel} in
20         1) date +"%Y-%m-%d %H:%M";;
21         2) echo -n "请输入新的日期(MMDDhhmm[[CC]YY])："
22            read da
23            date ${da};;
24         3) who -u | awk ‘{print $1}‘;;
25         4) shutdown -r now;;
26         5) shutdown -h now;;
27         6) break;;
28     esac
29     read
30 done