漫步量化

RDMARemote Direct Memory Access (RDMA) is a direct memory access from the memory of one computer into that of another without involving either one’s operating system.This permits high-throughput, low-latency networking, which is especially useful in ma..

OverviewThose who cannot remember the past are condemned to repeat it - George SantayanaCacheA Cache is a hardware or software component that stores data so that future requests for that data can be served faster.CPU cacheA CPU cache is a hard..

OverviewFrom google styleguide, Most .py files do not need to start with a #! line.Start the main file of a program with #!/usr/bin/env python3 (to support virtualenvs) or #!/usr/bin/python3 per PEP-394.This line is used by the kernel to find the Pyth..

OverviewThe inode (index node) is a data structure in a Unix-style file system that describes a file-system object such as a file or a directory.Each inode stores the attributes and disk block locations of the object’s data.Each file has an inode cont..

Overviewls - list directory contents-F, --classify​ append indicator (one of */=>@|) to entries, 在不同类型的文件的文件名结尾追加一个字符以示区别。可执行文件： *目录： /管道文件: |套接字文件: =普通文件: 无-1 : list one file per line, 只显示文件名，不像-l显示所有信息Referencesls(1) - Linux man ..

Overviewls - list directory contents-F, --classify​ append indicator (one of */=>@|) to entries, 在不同类型的文件的文件名结尾追加一个字符以示区别。可执行文件： *目录： /管道文件: |套接字文件: =普通文件: 无-1 : list one file per line, 只显示文件名，不像-l显示所有信息Referencesls(1) - Linux man ..

chownchange file owner and group.chown [-cfhvR] [--help] [--version] user[:group] file...chmod go-wgo-rwx removes read, write, execute permissions from the group and other users.It will not change permissions for the user that owns the file.chmo..

JavaJava is a set of computer software and specifications developed by James Gosling at Sun Microsystems, which was later acquired by the Oracle Corporation, tha provides a system for developing application software and deploying it in a cross-platform ..

OverviewNormally, you see two types of downloads avaiable for Windows platforms:x86 for 32bitx64 (or AMD64 or x86-64) for 64bitThe x in x86 means any member of the x86 family, such as 286(16-bit), 386(32-bit), 486 …, all of which were based on the ..

Nautilus file managerChapter 6 : Nautilus File ManagerGNOME Files, formerly and internally known as Nautilus, is the official file manager for the GNOME desktop.GNOME is a free and open-source desktop environment for Unix-like operating systems.R..

Unix domain socketA Unix domain socket or IPC socket(inter-process communication socket) is a data communication endpoint for exchanging data between processes executing on the same host OS.Valid socket types in the UNIX domain are:sock_stream : for ..

Seccompseccomp (short for secure computing mode) is a computer security facility in the Linux kernel.seccomp allows a process to make a one-way transition into a “secure” state where it cannot make any system calls exit(), sigreturn(), read(), write() ..

curl《理解TLSv1.2||JVM||libcurl||curl||RHEL||SLES》github《阮一峰：curl初学者教程》《阮一峰：curl的用法指南》Curl Cookbook各类参数-o 保存网页，相当于wget；-L 自动跳转-i 显示http response的头信息，连同网页代码；-I 只显示http response的头信息；-v 显示一次http通信的整个过程，包括端口连接和http request头信息；--trace 更详细的通信过curl..

Single Page Application (SPA)A single-page application (SPA) is a web application or website that interacts with the user by dynamically rewriting the current web page with new data from the web server, instead of the default method of browser loading e..

TLSv1.2Transport Layer Security (TLS), and its now-deprecated predecessor, Secure Sockets Layer (SSL), are cryptographic protocols designed to provide communications security over a computer network.TLS 1.2 was defined in RFC 5246 in August 2008.SLE..

archive fileAn archive file is a file that is composed of one or more computer files along with metadata.Archive files are used to collect multiple data files together into a single file for easier portability and storage, or simply to compress files t..

OverviewThe ip command is a Linux net-tool for system and network administators.The ip command replaces old good and now deprecated ifconfig command on modern Linux distributions.用法ip [options] OBJECT COMMANDip addr # 查看ipetho means Ethernet, wl..

问题描述直接运行docker 命令出现:Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://~images/json: dial unix /var/run/docker.sock: connect: permission deniedsudo docker 执行命令才可以.解决方案If you want ..

问题描述通过VS Code在window上wsl界面运行程序,出现上述错误.-bash: /usr/lib/command-not-found: /usr/bin/python3: bad interpreter: No such file or directory解决方案两种解决方案:如果/usr/bin/python3存在,将/usr/bin加入PATH如果/usr/bin/python3不存在,创建软链接...

问题描述Window下使用VS Code,在terminal中select default shell ,选择WSL bash.此时,ternimal里是wsl,正常使用Linux命令,想要运行一个python文件有几种方案:ternimal里直接python file.py菜单栏-Terminal--Run Active File右键--Run Python File In Terminal(Ctrl+Shift+F10)1,2本质一样,可以正常运行.3此时调用的是Window路径,..

envA list of all the current environmental variables and their values for the current user, including all the directories in the PATH variable, can be seen by running the env command without any options or arguements.PATHPATH is an environmental var..

Inode索引节点Each file has an inode containing metadata about the file.An application can retrieve this metadata using stat or statxdf -i # 查看每个硬盘分区的inode总数和已经使用的数量sudo dumpe2fs -h /dev/hda | grep "Inode size" # 查看每个inode节点的大小ls -i example.txt # 查看文件名对..

缘起安装docker 版本的grafana,官方推荐基于Alpine的版本.Alpine Linux projectSmall. Simple. Secure.Alpine Linux is a security-oriented, lightweight Linux distribution based on musl libc and busybox.musl libcmusl is an implementation of the C standard library buil..

shell pipelineTo successfully write a shell script, we have to do three things:Write a scriptGive the shell permission to execute itPut it somewhere the shell can find itWrite a scriptA shell script is a file that contains ASCII text.vim..

问题描述安装docker过程中需要add Docker’s official GPG key.curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -Why do we needThis is not Docker-specific. Most Linux package managers have the ability to validate the itegrity of a softwa..

Overviewr1中提到这种错误可能是timeout问题,加上timeout确实可以让程序失败后自动退出,但是不解决问题.此处问题可能是因为rsync使用了z,即压缩传输.但是传输是很多小体量的文件,加上z反而速度慢了,因为瓶颈从网络io转移到了CPU计算,通过top可以看到rsync占用大量cpu,因为cpu性能不够所以卡死.此处去掉,问题解决Referencesrsync文件同步失败问题排查记录Bug 645236 - with big file, rsync times ..

Unix-like OSuname -mWindows右键我的电脑—属性x86_64 vs. 64位x86-64(also known as x64, x86_64, AMD64 and Inter 64) is the 64-bit version of the x86 instruction set.It introduces two new modes of operation, 64-bit mode and compatibility mode, along with a..

What is shsh (or the Shell Command Language) is a programming language described by the POSIX standard.It has many implementations(ksh88, dash, …). bash can also be considered an implememtation of sh.Because sh is a specification, not an implementatio..

问题描述rsync通过ssh将本地数据同步到远程服务器,需要交互式输入密码.从Linux命令大全/rsync可以看到有一个参数--password-file=FILE, 可以从FILE中获得密码.对于这个FILE,要求600权限.适用上述参数出现:The --password-file option may only be used when accessing an rsync daemon《rsync 原生的无密码同步方法记录》这里给出了详细解释，还是有些复杂优选方案讲ssh设..

symbolic link软连接，本质是Unix概念，不是Python概念。link in UnixA link in UNIX is a pointer to a file.Like pointers in any programming languages, links in UNIX are pointers pointing to a file or a directory.Creating links is a kind of shortcuts to access a file..

rsyncrsync – a fast, versatile, remote (and local) file-copying tool.阮一峰的教程介绍的很详细。Referencesrsync 用法教程 (阮一峰)Linux 命令大全Welcome to the rsync web pagesrsync(1) - Linux man page

问题描述使用nohup启动程序，出现上述情况。解决方案It’s not an error.It’s nomarl behavioer. It just informs you that once started the in/output is removed from your console.To avoid the message you need to start it like :nohup python script.py 2>&1 &Refer..

apt-get updateupdates the list of avaible packages and their versions, but it does not install or upgrade any packagesapt-get upgradeactually installs newer versions of the packages you have. After updating the lists, the package manger knows about ..

Symbolic linksUbuntu keeps track of the default programs by maintaining a list of symbolic links, under /etc/alternatives directory. Each entry here is a shortcut points to the actual program, which may have more than one option.update-alternatives..

Version Control repository management servicesVersion Control repository management services are a key component in the software development workflow.When talking about the differences and similarities of GitLab vs. GitHub, we need to look betond cod..

umaskFrom wikipedia, umask is a command that determines the settings of a mask that controls file permissions are set for newly created files. It may also affect how the file permissions are changed explicitly. umask is also a function that sets the m..

查看整个服务器df -hl查看du -h --max-depth=1 dirdf vs. dudf 查看当前linux系统上的文件系统的磁盘使用情况统计du用于显示目录或文件的大小Referencesdf vs. du: why so much difference? [duplicate]

查看版本uname -r Display kernel release -a Display all information -o Display the operating system -v Display kernel version hostnamectl # display information about the system's network configurationcat /proc/version # Displays the contents of..

安装过程# 下载cd /tmpcurl -O https://repo.anaconda.com/archive/Anaconda3-2020.02-Linux-x86_64.sh # https://www.anaconda.com/products/individual# 校验sha256sum Ana..# 安装bash Anaconda3-2020.02-Linux-x86_64.sh # 一路yes# 更新bashsource ~/.bashrcReference..

源码安装参见tutorialspoint，总是失败apt安装其实很简单，Ubuntu下sudo apt install nasmExample源码filename.asm：section .datamsg db "Hello World", 10msglen equ $-msgsection .textglobal _start_start:mov rax,1mov rdi,1mov rsi,msgmov rdx,msglensyscallmov rax..