shell——demo添加、删除用户

#!/bin/bash

#func:add or del user
#author:reed

. /etc/profile 可执行文件

UserCtr=$1 参数
TeacherName=$2
StudentName=$3
StudentNumber=$4

 #定义函数
  提示信息

Usage(){
cat<<EOF重定向
–Usage:
$0 [add/del] [Teacher’sName] [Student’sName] [The number of Students]
ex.
$0 add teacher stu 3
–
add:useradd username 添加用户
del:userdel username 删除用户
[Teacher’sName]:teacher’s name[Student’sName]:student’s name,just only the beginning of a lowercase letter
[The number of Students],only [1-10]
EOF
}

命令 chmod u+x demo.sh
./demo.sh add zhanglaoshi student 5

if [ KaTeX parse error: Expected 'EOF', got '#' at position 1: #̲ -eq 4 ];then …#所有参数总和 add zhanglaoshi student 5**
if [ $1 == “add” ];then //第一个参数
#echo “add”
if [[ " $2" =~ ^[a-z]+$ && " $3" =~ ^[a-z]+$ //以小写字母开始 && “$4” -ge 1 && “$4” -le 10 //学生个数范围]];then
#create user $2
id $2 >>/dev/null 2>&1
//id用户的详细信息，检查用户是否存在 ，2>&1 ,把输入输出的信息都定向到黑洞中，否则 2>>/dev/null
if [ $? -ne 0 ];then **//$? 上一条命令的返回值**
useradd $2 **//教师用户** TeacherPasswd=$(date|md5sum|cut -c 1-6) //教师用户密码 date 日期，md5sum 对时间加密，加密方式，数字或字母，cut -c 截取一到六位，这样密码不会重复
echo $TeacherPasswd|passwd --stdin $2 >>/dev/null 2>&1 //将程序中的变量值作为键盘的标准输入
echo “User [$2] create successfully.”
echo “ $2:$TeacherPasswd”
else
echo “The user [$2] is exist.”
Fi
//创建普通学生用户
for ((num=1;num<=$4;num++));do
id ${3}${num} >>/dev/null 2>&1
if [ $? -ne 0 ];then
useradd ${3}${num}
StudentPasswd=$(echo $RANDOM|md5sum|cut -c 1-6) **//$RANDOM随机数**
echo $StudentPasswd|passwd --stdin ${3}${num} >>/dev/null 2>&1
echo “User [ ${3}${num}] create successfully.”
echo “ ${3}${num}: $StudentPasswd" else echo "The user [${3}${num}] is exist.”
fi
done
else
echo “Parameter error!”
exit 10000
fi
elif [ $1 == “del” ];then
id $2 >>/dev/null 2>&1
if [ $? -ne 0 ];then
userdel $2
echo "User [$2] del successful”
else
echo “The user [$2] is not exist.”
fi
for((num=1;num<=$4;num++));do
id ${3} ${num} >>/dev/null 2&1
if [ $? -ne 0 ];then
Userdel ${3}${num}
echo “user [ ${3}${num} delete successfully”
else
echo “the user [ ${3}${num}] is not exist”
fi
else
echo “Parameter error!Please input [add] or [del].”
exit 10086
fi
else
Usage
fi

   cat-c   --characters=LIST
          select only these characters