shell脚本之指定添加、删除参数来添加、删除多个指定用户

1、指定--useradd、--userdel添加、删除用户参数
2、指定特定的用户，对其进行增加或者删除操作

#!/bin/bash
if [ $#  -lt 1 ];then
        echo "Usage:./adminuser.sh  --useradd | --userdel ARG1,ARG2,ARG3..."
        exit 2
fi
username=`echo "$2" | sed "s/,/ /g"`  #将脚本参数指定的用户名转换为列表，以便进行for循环
if [ $1 == "--useradd" ];then                                              
        for i  in $username;do
                if id $i &> /dev/null;then
                        echo "$i have existed"
                else
                        useradd $i &>/dev/null
                        echo "$i is created successfully"
                        echo "$i" | passwd --stdin $i &>/dev/null
                fi  
        done
elif [ $1 == "--userdel" ];then
        for i  in $username;do
                if id $i &>/dev/null;then
                        userdel -r $i &>/dev/null
                        echo "$i is deleted"
                else 
                        echo "$i is not exist"
                fi  
        done
else
        echo "Unknow Arguments"
fi