Linux shell 实现用户自动修改成随机密码

#!/bin/bash
echo "********************************************"
echo "*                                          *"
echo "*     change all user  ==> A               *"
echo "*     other      user  ==> username        *"
echo "*                                          *"
echo "********************************************"

read -p "all_user or one_username :   " A

if [ $A == "A" ];then
        username=$(cat /etc/passwd|grep 'bin/bash'|grep -v root|awk -F ":" '{print $1}')
else
        username=$A
fi

function make_passwd {
pw=$(openssl rand -base64 12|egrep -v "0|o|l|I|1"|tr "+|/|'\'" '$')
}

IP=$(ifconfig|sed -n 2p|awk -F " " '{print $2}')
Hostname=$(echo `hostname`_`echo $IP|awk -F "." '{print $3,$4}'`|tr ' ' '_')

for user in $username
do
        while true
        do
                make_passwd
                if [ -n "$pw" ];then
                        echo "$pw" |passwd --stdin $user >> /dev/null 2>&1
                        echo -e "$Hostname\t$IP\t$user\t$pw"
                break
                fi
        done

done