简述DHCP的流程？ 新节点通过DHCP获取地址信息的主要流程有如下四个过程： 1、寻找DHCP Server 客户机第一次登录网络的时，向网络上发出一个DHCPDISCOVER广播（包中包含客户机的MAC地址和计算机名等信息）。其源地址为0.0.0.0，目标地址为255.255.255.255。 2、提供IP地址租用 服务端监听到客户机发出的DHCP discover广播后，从剩余地址池中选择最前面的空置IP，连同其它TCP/IP设定，通过广播方式响应给客户端一个DHCP OFFER数据包（包中包含IP地址、子网掩码、地址租期等信息）。源IP地址为DHCP Server的IP地址，目标地址为255.255.255.255。同时，DHCP Server为此客户保留它提供的IP地址，从而不会为其他DHCP客户分配此IP地址。 3、接受IP租约 客户机挑选最先响应的DHCP OFFER（一般是最先到达的那个），同时向网络广播DHCP REQUEST数据包（包中包含客户端的MAC地址、接受的租约中的IP地址、提供此租约的DHCP服务器地址等），声明将接受某一台服务器提供的IP地址。此时，由于还没有得到DHCP Server的最后确认，客户端仍然使用0.0.0.0为源IP地址，255.255.255.255为目标地址进行广播。 4、租约确认 服务端接收到客户端的DHCP REQUEST之后，会广播返回给客户机一个DHCP ACK消息包，表明已经接受客户机的选择，并将这一IP地址的合法租用以及其他的配置信息都放入该广播包发给客户机。 客户机在接收到DHCP ACK广播后，会向网络发送三个针对此IP地址的ARP解析请求以执行冲突检测，查询网络上有没有其它机器使用该IP地址；如果发现该IP地址已经被使用，客户机会发出一个DHCP DECLINE数据包给DHCP Server，拒绝此IP地址租约，并重新发送DHCP discover信息。此时，在DHCP服务器管理控制台中，会显示此IP地址为BAD_ADDRESS。 如果网络上没有其它主机使用此IP地址，则客户机的TCP/IP使用租约中提供的IP地址完成初始化，从而可以和其他网络中的主机进行通讯。

简述FTP两种登录方式以及两种传输模式？ FTP有两种登录方式：匿名登录和授权登录。 使用匿名登录时，用户名为：anonymous，密码为：任何合法email地址；使用授权登录时，用户名为用户在远程FTP系统中的用户帐号，密码为用户在远程系统中的用户密码。 区别：使用匿名登录只能访问FTP目录下的资源，默认配置下只能下载；而授权登录访问的权限大于匿名登录，且上载、下载均可。

简述FTP主要的工作模式？ FTP工作模式是以服务端角度来区分，有主动模式和被动模式。

简述Linux中常见的系统服务，其作用分别是？ 常见的系统服务及其作用有： NTP/Chrony：用于时钟同步； DHCP：动态主机配置协议，用于自动分配主机地址，默认使用UDP 63端口； DNS：域名解析，运行在UDP协议之上，默认使用53端口； NFS：网络文件系统，依赖于RCP协议，其基本原则是“容许不同的客户端及服务端通过一组RPC分享相同的文件系统”，它是独立于操作系统，容许不同硬件及操作系统的系统共同进行文件的分享。 Postfix：邮件服务； rsync：远程数据备份服务。 VPN：虚拟专用网。

On Ubuntu 16.04 LTS, I successfully used the following to disable suspend: sudo systemctl mask sleep.target suspend.target hibernate.target hybrid-sleep.target And this to re-enable it: sudo systemctl unmask sleep.target suspend.target hibernate.target hybrid-sleep.target

linux-timemachine

What won’t change is people’s tendency toward gossip, tribalism driven by gossip and the ability of anybody to inform anybody else about anything, including wrongly. The only places where news won’t skew fake will be localities in the natural world. That’s where the digital and the physical connect best. Also expect the internet to break into pieces, with the U.S., Europe and China becoming increasingly isolated by different value systems and governance approaches toward networks and what runs on them.

What happened here is that the file 'somefile.txt' is encoded in UTF-16, but your terminal is (probably) by default set to use UTF-8.  Printing the characters from the UTF-16 encoded text to the UTF-8 encoded terminal doesn't show an apparent problem since the UTF-16 null characters don't get represented on the terminal, but every other odd byte is just a regular ASCII character that looks identical to its UTF-8 encoding.

All of these values, including the precious contents of the private key file, can be seen via ps when these commands are running. ps finds them via /proc/<pid>/cmdline, which is globally readable for any process ID.

chrome用的是server_proxy这个变量，而且是在启动时设置才生效。

ufw allow OpenSSH ufw allow "Nginx Full" once NGINX is installed. ufw enable

If you haven't seen it yet, check out the PinePhone Pro and its docking station. Much like the Steam Deck's docking station, it plugs the phone into a monitor, keyboard, and mouse to turn your phone into a PC.

When Ubuntu was confronted with making Debian user friendly, the issue was speeding up software updates. Manjaro has the opposite issue with Arch and is handling it appropriately.

B/ Mainline kernel offers many ways to increase desktop responsiveness without the need to patch or reconfig it. Many tweaks can be activated using the cfs-zen-tweaks you can download and just run but I would advise you just read the very simple code and learn how each of the tweaks impact. Don't hesitate to lower the priority of your cpu-bound processes (compilations, simulations...) and increase the priority of your interactive tasks thanks to the renice command and even change their scheduling policy using chrt Ultimately, you can always pin interrupts to dedicated cpus (setting desired values in /proc/irq/[irq_id]/smp_affinity) , having one in charge of the keyboard and the mouse, another one for the graphic adaptor a third one for the sound card and a fourth one housekeeping for all the possible remaining. Just plenty of solutions left opened without changing a byte in your distro-kernel.

Points from the comments in support of using Mac

Points from the comments in support of using Linux

on an Intel/AMD PC or Mac, docker pull will pull the linux/amd64 image. On a newer Mac using M1/M2/Silicon chips, docker pull will the pull the linux/arm64/v8 image.

In order to meet its build-once-run-everywhere promise, Docker typically runs on Linux. Since macOS is not Linux, on macOS this is done by running a virtual machine in the background, and then the Docker images run inside the virtual machine. So whether you’re on a Mac, Linux, or Windows, typically you’ll be running linux Docker images.

For sufficiently simple cases, just running a few commands sequentially, with no subshells, conditional logic, or loops, set -euo pipefail is sufficient (and make sure you use shellcheck -o all).

脚本学习_Linux_Sed命令_替换

如何清理Linux服务器磁盘空间？

systemd 为什么会有那么大的争议？

如何系统地学习Shell编程？

一个成熟的自动化运维系统具备什么功能？

如何学习 Linux 命令行，有哪些经验思路和方法？

如何更深入地学习 Linux？

如何控制Linux清理cache机制?

求推荐好用的linux下管理面板？

Linux 内核学习的经典书籍及途径？

First, if Jenkins runs as PID 1, then it's difficult to differentiate between process that were re-parented to Jenkins (which should be reaped), and processes that were spawned by Jenkins (which shouldn't, because there's other code that's already expecting to wait them).

SIGTSTP is like SIGSTOP except that it can be caught and handled.

SIGSTOP and SIGKILL are two signals that cannot be caught and handled by a process.

The process group mechanism in most Unix-like operating systems can be used to help protect against accidental orphaning, where in coordination with the user's shell will try to terminate all the child processes with the "hangup" signal (SIGHUP), rather than letting them continue to run as orphans.

its jobs (internal representation of process groups)

And get a list of characters in a font like this:

The newer GPT standard is paired with UEFI BIOS systems

Throughout the drive

and have either a black or blue-screen-of-death background color.

The BIOS does things like configure the keyboard, mouse, and other hardware, set the system clock

support a GPT partition table and a UEFI BIOS.

very easy to ruin the MBR sector of the drive, making it impossible to boot up again. Then you'll either need to create a recovery USB drive with Windows or Linux and try to repair the MBR, or completely wipe the drive and reinstall the operating system

There are dedicated tools to verify checksum of files in Linux. You can also check hashes in the Nautilus file manager with nautilus-gtkhash extension.

Receiving a GPG error when running apt-get update? Your default umask may not be set correctly, causing the public key file for the repo to not be detected. Run the following command and then try to update your repo again: sudo chmod a+r /etc/apt/keyrings/docker.gpg.

Add Docker’s official GPG key: $ sudo mkdir -p /etc/apt/keyrings $ curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg Use the following command to set up the repository: $ echo \ "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu \ $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

Used to explicitly set the container hostname. If you don't specify the hostname, it defaults to the container ID, which is a randomly generated system GUID.

Map a TCP port on the host environment (first value) with a TCP port in the container (second value). In this example, SQL Server is listening on TCP 1433 in the container and this container port is then exposed to TCP port 1433 on the host.

Specify a custom SQL Server collation, instead of the default SQL_Latin1_General_CP1_CI_AS.

The SA_PASSWORD environment variable is deprecated. Please use MSSQL_SA_PASSWORD instead.

About tmux

gpg -d <yadm archive file> | tar tvf -

echo testing | gpg -e -r <recipient> | gpg

sudo usermod -aG sambashare $USER

The custom title bar has been a success on Windows, but the customer response on Linux suggests otherwise. Based on feedback, we have decided to make this setting opt-in on Linux and leave the native title bar as the default. The custom title bar provides many benefits including great theming support and better accessibility through keyboard navigation and screen readers. Unfortunately, these benefits do not translate as well to the Linux platform. Linux has a variety of desktop environments and window managers that can make the VS Code theming look foreign to users.

If your laptop is extremely old then I would recommend Puppy Linux.If your laptop isn’t very old but doesn’t perform very well I would recommend AntiX.If your laptop is a little old but still can’t handle Windows 7/10 very well I would recommend Lubuntu.

So the correct command to use is findmnt, which is itself part of the util-linux package and, according to the manual: is able to search in /etc/fstab, /etc/mtab or /proc/self/mountinfo

The main problem of the Linux community is that it is divided. I know this division represents freedom of choice but when your rivals are successful, you must inspect them carefully. And both rivals here (MacOS and Windows) get their power from the "less is more approach".This division in Linux communities make people turn into their communities when they have problems and never be heard as a big, unified voice.When something goes wrong with other OSes, people start complaining in many forums and support sites, some of them writing to multiple places and others support them by saying "yeah, I have that problem, too".In the Linux world, the answers to such forums come as "don't use that shitty distro" or "use that command and circumvent the problem".Long story short" average Linux user doesn't know that they are:still customers and have all the rights to demand from companiesthey can get together and act up louder.Imagine such an organizing that most of the Linux users manage to get together and writing to Netflix. Maybe not all of them use Netflix but the number of the Linux users are greater than Netflix members. What a domination it would be!But instead we turn into our communities and act like a survival tribe who has to solve all their problems themselves .

Big Software companies like Adobe or Netflix do two things that are relevant for us and currently go wrong:They analyse the systems their customers use. They don't see their Linux users because we tend to either not use the product at all under Linux (just boot windows, just use a firertv stick and so one) or we use emulators or other tools that basically hide that we actually run Linux. --> The result is that they don't know how many we actually are. They think we are irrelevant because thats what the statistics tell them (they are completely driven by numbers).They analyze the feature requests and complains they get from their customers. The problem is: Linux users don't complain that much or try to request better linux support. We usually somehow work around the issues. --> The result is that these companies to neither get feature requests for better Linux support nor bug reports from linux users (cause its not expected to work anyways).

Create .bash_profile in your home directory and add these lines: export SHELL=/bin/zsh exec /bin/zsh -l

查看内存信息1）使用free命令默认单位为K，可通过结合参数-b、-k、-m分别以单位B、K、M进行显示

If you are on Linux, you can simply download it from GitHub but the most convenient way is to use the pyenv-installer that is a simple script that will install it automatically on your distro, whatever it is, in the easiest possible way.

How to Change Colors on LS in Bash

What worked for me was to use the following command to send the VT320 "unhide" command sequence:

I sometimes wondered why the VS Code team put so much effort into the built-in terminal inside the editor. I tried it once on Linux and never touched it again, because the terminal window I had right next to my editor was just massively better in every way. Having used Windows terminals for a while, I now fully understand why it’s there.

They just automate the process of going to the website, downloading an installer and then running it - which is slightly better than doing it yourself.

Desktop Linux is often criticized for this, but Windows is much worse, somehow! It’s really inconsistent. Half of it is “new” UI and half of it is old Win32/GDI type UI - just as bad as KDE/GTK - except worse, because you can’t configure them to use the same theme. Also, when you install a Linux distribution, it’ll start off either all KDE or all GTK, or whatever - but with Windows you’re stuck with a random mix of both right from the start.

usb-devices

lsusb -t

level 1Fatal_Taco · 2 days ago · edited 2 days agoArch Linux, and likely most distros, are defined by these few things and are not limited to:The Linux Kernel, what type of config and modules it's been compiled with.The pre-packaged programs it comes with by default.The init.The package manager.The repositories it references.The slightly differing Linux Filesystem Hierarchy.The types of computers it runs on.

15 Little-Known Unix Commands

37 Important Linux Commands You Should Know

리눅스 아재력 or 할배력 셀프 테스트

The Linux command-line cheat sheet

Linux Productivity Tools

LXC, is a serious contender to virtual machines. So, if you are developing a Linux application or working with servers, and need a real Linux environment, LXC should be your go-to. Docker is a complete solution to distribute applications and is particularly loved by developers. Docker solved the local developer configuration tantrum and became a key component in the CI/CD pipeline because it provides isolation between the workload and reproducible environment.

== and != for string comparison -eq, -ne, -gt, -lt, -le -ge for numerical comparison

> will overwrite the current contents of the file, if the file already exists. If you want to append lines instead, use >>

The syntax for “redirecting” some output to stderr is >&2. > means “pipe stdout into” whatever is on the right, which could be a file, etc., and &2 is a reference to “file descriptor #2” which is stderr.

single quotes, which don’t expand variables

This only works if you happen to have Bash installed at /bin/bash. Depending on the operating system and distribution of the person running your script, that might not necessarily be true! It’s better to use env, a program that finds an executable on the user’s PATH and runs it.

uix includes package definitions for many GNU and non-GNU packages, all of which respect the user’s computing freedom. It is extensible: users can write their own package definitions (see Defining Packages) and make them available as independent package modules (see Package Modules). It is also customizable: users can derive specialized package definitions from existing ones, including from the command line (see Package Transformation Options).

snap list --all and remove with snap remove --revision XXX gnome-3-26-1604

All operating systems with network support have a hosts file to translate hostnames to IP addresses. Whenever you open a website by typing its hostname, your system will read through the hosts file to check for the corresponding IP and then open it. The hosts file is a simple text file located in the etc folder on Linux and Mac OS (/etc/hosts). Windows has a hosts file as well, on Windows you can find it in Windows\System32\drivers\etc\if(typeof __ez_fad_position!='undefined'){__ez_fad_position('div-gpt-ad-vitux_com-box-3-0')};

-xcf cursorfile cursorsize This lets you change the pointer cursor to one loaded from an Xcursor file as defined by libXcursor, at the specified size.

This runs a loop 555 times. Takes a screenshot, names it for the loop number with padded zeros, taps the bottom right of the screen, then waits for a second to ensure the page has refreshed. Slow and dull, but works reliably.

#!/bin/bash
for i in {00001..00555}; do
   adb exec-out screencap -p > $i.png
   adb shell input tap 1000 2000
   sleep 1s
done
echo All done

:w !sudo tee %

special permission bit at the end here t, this means everyone can add files, write files, modify files in the /tmp directory, but only root can delete the /tmp directory

kpartx /path/to/chromeos.img

I find some of XDG's default dirs, especially ~/.local/share/whatever, to be very annoying. (Almost as annoying as having ~/snap polluting my home dir, but for a different reason.) I shouldn't have to type such long paths or navigate three folders deep in order to access my data files. I therefore make use of the XDG_DATA_HOME environment variable for XDG-style programs, so they will put my files somewhere convenient. However, I don't think Snap can honor that variable, because AppArmor rules require fixed paths. Given 1 & 2, I think ~/.snap/data is a sensible compromise, at least until the underlying components are flexible enough to let the user choose.

$@ is all of the parameters passed to the script. For instance, if you call ./someScript.sh foo bar then $@ will be equal to foo bar.

The solution is absolutely straightforward and posting it *will* be embarrassing.

管線命令僅會處理 standard output，對於 standard error output 會予以忽略 管線命令必須要能夠接受來自前一個指令的資料成為 standard input 繼續處理才行。

x-systemd-automount

I find it much simpler to use a partition label with LABEL=.... It is shorter, easier to remember, and also has the advantage that should the partition go bad and need to be replaced you can create a new partition, give it the same label provided the old partition is either removed or at least changed to be unlabelled and fstab will never know the difference.

sudo apt-get autoclean sudo apt-get autoremove sudo apt-get clean sudo apt update sudo apt-get dist-upgrade --fix-missing sudo apt-get dist-upgrade --fix-broken sudo apt full-upgrade sudo apt -f install dpkg --configure -a

The best practice is this: #!/usr/bin/env bash #!/usr/bin/env sh #!/usr/bin/env python

Here's my bash boilerplate with some sane options explained in the comments

set -euo pipefail

AUR

How to Install MX Linux in VirtualBox on Windows 10

CBL-Mariner is an internal Linux distribution for Microsoft’s cloud infrastructure and edge products and services.