创建用户设置随机密码

#!/bin/bash
####我们在这以8位为例
x=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
for i in {1..8}
do
NUM=$[RANDOM%62]
PASS=${x:NUM:1}
PASS1=${PASS1}$PASS
done

read -p "请输入您创建的用户名：" user
[ -z $user ] && exit
[ ! -z echo $user | awk '{print $2}' ] && exit
[ ! -z echo $user | sed 's#[0-9]##g' | sed 's#[a-Z]##g' ] && exit
useradd $user

echo "$PASS1" | passwd --stdin $user > /dev/null
echo -e "$PASS1\t$user" >> mail.txt ####### 管理员备份
read -p "请输入您的邮箱帐号：" mail
echo "用户：$user 密码：$PASS1" | mail -s "新建用户$user的密码" -r admin $mail
#######新手第一次写 多多指教