main ps:

Here are the different values that the s, stat and state output specifiers (header "STAT" or "S") will display to describe the state of a process:

D    uninterruptible sleep (usually IO)
I    Idle kernel thread
R    running or runnable (on run queue)
S    interruptible sleep (waiting for an event to complete)
T    stopped by job control signal
t    stopped by debugger during the tracing
W    paging (not valid since the 2.6.xx kernel)
X    dead (should never be seen)
Z    defunct ("zombie") process, terminated but not reaped by its parent

For BSD formats and when the stat keyword is used, additional characters may be displayed:

<    high-priority (not nice to other users)
N    low-priority (nice to other users)
L    has pages locked into memory (for real-time and custom IO)
s    is a session leader
l    is multi-threaded (using CLONE_THREAD, like NPTL pthreads do)
+    is in the foreground process group

监视指定主机的数据包

打印所有进入或离开sundown的数据包.

tcpdump host sundown

也可以指定ip,例如截获所有210.27.48.1 的主机收到的和发出的所有的数据包

tcpdump host 210.27.48.1 

打印helios 与 hot 或者与 ace 之间通信的数据包

tcpdump host helios and ( hot or ace )

截获主机210.27.48.1 和主机210.27.48.2 或210.27.48.3的通信

tcpdump host 210.27.48.1 and (210.27.48.2 or 210.27.48.3 ) 

打印ace与任何其他主机之间通信的IP 数据包, 但不包括与helios之间的数据包.

tcpdump ip host ace and not helios

如果想要获取主机210.27.48.1除了和主机210.27.48.2之外所有主机通信的ip包，使用命令：

tcpdump ip host 210.27.48.1 and ! 210.27.48.2

截获主机hostname发送的所有数据

tcpdump -i eth0 src host hostname

监视所有送到主机hostname的数据包

tcpdump -i eth0 dst host hostname

Sed Command to Delete Lines: Sed command can be used to delete or remove specific lines which matches a given pattern or in a particular position in a file. Here we will see how to delete lines using sed command with various examples.

CentOS8 的生命周期到2021年12月31日截止，CentOS7是到2024年6月30日。还有使用CentOS8的注意了，官方可能不再更新，需要将系统升级到CentOS Stream.

升级也很简单：

dnf swap centos-linux-repos centos-stream-repos
dnf distro-sync

附 CentOS Stream 下截地址：

http://mirrors.cqu.edu.cn/CentOS/8-stream/isos/x86_64/
http://mirrors.aliyun.com/centos/8-stream/isos/x86_64/
http://mirrors.neusoft.edu.cn/centos/8-stream/isos/x86_64/
http://mirrors.163.com/centos/8-stream/isos/x86_64/
http://mirrors.tuna.tsinghua.edu.cn/centos/8-stream/isos/x86_64/
http://mirrors.ustc.edu.cn/centos/8-stream/isos/x86_64/
http://ftp.sjtu.edu.cn/centos/8-stream/isos/x86_64/
http://mirrors.nju.edu.cn/centos/8-stream/isos/x86_64/
http://mirrors.bfsu.edu.cn/centos/8-stream/isos/x86_64/

awk

文本和数据进行处理的编程语言

补充说明

awk 是一种编程语言，用于在 linux/unix 下对文本和数据进行处理。数据可以来自标准输入(stdin)、一个或多个文件，或其它命令的输出。它支持用户自定义函数和动态正则表达式等先进功能，是 linux/unix 下的一个强大编程工具。它在命令行中使用，但更多是作为脚本来使用。awk 有很多内建的功能，比如数组、函数等，这是它和 C 语言的相同之处，灵活性是 awk 最大的优势。

awk 命令格式和选项

语法形式

awk [options] 'script' var=value file(s)
awk [options] -f scriptfile var=value file(s)

 - name: set hostname
   hostname:
     name: "pardus"

ansible execute failed on aarch64 platform, to fix this:

 - name: set hostname
   hostname:
     name: "pardus"
     use: systemd

append use: systemd .

pip 安装gevent时报出这些错：
重点看这个：ERROR: Failed building wheel for cffi

64位系统安装踩搞不少，很多apt都装不了，只能看官方有没有deb包，实在不行就需要编译安装。

可以从这里找docker的包
https://download.docker.com/linux/debian/dists/buster/pool/stable/armhf/

需要下载这三个 wget xxx