从来不用国内的服务，但是没有办法，为了速度还是只能在国内找，矮子里挑个高的，只能选择阿里云。。。但是随之而来的是各种大坑。。

ECS 封掉了25端口，也就是说你不能在上面创建任何邮件服务器。。。阿里云工单的回答是，只能使用阿里云云邮箱或者第三方，需要修改代码。。。

修改你妹妹啊。。我是直接用bash 调用postfix做发件服务，没有代码。。。

找了一晚上加一上午，目前最好的办法就是使用qq 的免费企业邮箱。。但是qq 比较鬼的是。。他在文档中没有标明有587端口。。但是你确可以使用这个端口。。。465 是ssl 端口，这样配置起来会比较麻烦。。

首先是创建qq的免费企业邮箱，得到smtp 信息

smtp:  smtp.exmail.qq.com:587

TLS

然后在centos 里面安装postfix 和 sasl 模块

sudo yum install postfix cyrus-sasl cyrus-sasl-lib cyrus-sasl-plain -y

编辑 /etc/postfix/main.cf, 然后加上

relayhost = [smtp.exmail.qq.com]:587

smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_use_tls = yes
smtp_tls_CAfile = /etc/ssl/certs/ca-bundle.crt
smtp_sender_dependent_authentication = yes
smtp_generic_maps = hash:/etc/postfix/generic

在/etc/postfix/sasl_passwd 里面写用户名和密码, 比如说用户名为 [email protected], 密码为iamhippo, 那么就这么写:

[smtp.exmail.qq.com]:587 [email protected]:iamhippo

在/etc/postfix/generic 要重写mail from 的地址，假如你的hostname 是i.iamhippo.com, 那么就可以写成:

@i.iamhippo.com [email protected]

 

最后就是生成hash 数据库了：

postmap /etc/postfix/sasl_passwd
postmap /etc/postfix/generic
chmod 600 /etc/postfix/sasl_passwd*

然后我们只需要重启postfix，就大功告成

service postfix restart

If you’ve used any flavour of Unix for development, you’ve probably installed software from source with this magic incantation:

./configure

make

make install

I know I’ve typed it a lot, but in my early days using Linux I didn’t really understand what it meant, I just knew that if I wanted to install software this was the spell to recite.

Recently I’ve been building my own Unix tools, and I wanted to tap into this standard install process; not only is it familiar to many Unix users, it’s also a great starting point for building a package for Homebrew and the various Linux and BSD package managers. It was time to dig into the Unix Grimoire and find out what the incantation does.更多

1. List Files using ls with no option

ls with no option list files and directories in bare format where we won’t be able to view details like file types, size, modified date and time, permission and links etc.

2 List Files With option –l

Here, ls -l (-l is character not one) shows file or directory, size, modified date and time, file or folder name and owner of file and it’s permission.

3. View Hidden Files with option -a

List all files including hidden file starting with ‘.‘.

4. List Files with Human Readable Format with option -lh

With combination of -lh option, shows sizes in human readable format.

5. List Files and Directories with ‘/’ Character at the end

Using -F option with ls command, will add the ‘/’ Character at the end each directory.

6. List Files in Reverse Order

The following command with ls -r option display files and directories in reverse order.

7. Recursively list Sub-Directories

ls -R option will list very long listing directory trees. See an example of output of the command.

8. Reverse Output Order

With combination of -ltr will shows latest modification file or directory date as last.

9. Sort Files by File Size

With combination of -lS displays file size in order, will display big in size first.

10. Display Inode number of File or Directory

We can see some number printed before file / directory name. With -i options list file / directory with inode number.

11. Shows version of ls command

Check version of ls command.