shell脚本，创建用户和组

User_Check(){
    #create group if not exists
    egrep "^$group" /etc/group >& /dev/null
    if [ $? -ne 0 ]
    then
        groupadd $group
    fi

    #create user if not exists
    egrep "^$user" /etc/passwd >& /dev/null
    if [ $? -ne 0 ]
    then
        useradd $user  -r -m  -g $group  -s"/bin/bash" -p "$(openssl passwd -1 $user)"
        ## add user to sudo group
        #for ubuntu
        usermod -aG sudo $user
        #for centos
        usermod -aG wheel $user
    fi
}