shell小实例

 编写一个脚本程序,当脚本执行时会在屏幕上输出以下画面,并实现相应的功能:
     *****************************************
     *           Linux User Manager          *
     *        1. Create User                 *
     *        2. Delete User                 *
     *        3. Update Password             *
     *        4. Add user to group           *
     *****************************************
   #vi /shell/userma
      #!/bin/bash
      menu() {
       clear
       echo "*****************************************"
       echo "*           Linux User Manager          *"
       echo "*        1. Create User                 *"
       echo "*        2. Delete User                 *"
       echo "*        3. Update Password             *"
       echo "*        4. Add user to group           *"
       echo "*****************************************"
      }
     
      cu() {
       while [ 1 -lt 2 ]
        do
       echo  -n "username:"
       read u
       if [ -z $u ]
         then
        echo "username error"
        continue
       fi
       if grep -q "^$u:" /etc/passwd
          then
        echo "user $u exists"
        contiune
       fi
       useradd $u
       break
         done
       }
      
      du() {
       echo -n "username:"
        read u
       if grep -q "^$u:" /etc/passwd
          then
        userdel $u
           else
         echo "user $u is not exists"
        fi
       }

       up() {
        echo -n "username:"
         read u
         if grep -q "^$u:"   /etc/passwd
            then
          passwd $u
              else
           echo "user $u is not exists"
         fi
        }
       
       ag() {
         echo -n "username:"
          read u
         echo -n "groupname:"
           read g
          if  grep -q "^$u:"   /etc/passwd
           then
             if grep -q "$g:" /etc/group
                 then
               gpasswd  -a $u $g
               fi
           fi
         }
         menu
          echo -n "please input choice:"
           read c
            case $c in
                1)
                cu
                  ;;
                2)
                 du
                  ;;
                3)
                  up
                   ;;
                4)
                  ag
                   ;;
                *)
                  echo "please input 1-4"
                     ;;
              esac