Linux Study -- Tour directory in Linux

Understanding the Filesystem Tree

    AUnix-like operation system such as Linux organizes its files in what is calleda hierarchical directory structure.This means that they are organized in a tree-likepattern of directories,which may contain files and other directories.The firstdirectory in the filesystem is called the root directory.The root directorycontains files and subdirectories,which contain more files and subdirectories,andso on.

    Unlike Windows,which has a separatefilesystem tree for each storage device,Unix-like systems such as Linux alwayshave a single filesystem tree,regardless of how many drives or storage devicesare attached to the computer.Storage devices are attached(or more correctly,mounted)atvarious points on the tree according to the whims of the system administrator.

 Tour directory in Linux

       COMMAND  pwd

       Acronymof Print working directory.

 

       COMMAND  ls

       Tolist the files and directories in the specified directory , default display thecurrent directory if we specified no directory.

 

       COMMAND cd

       Changethe current working directory.

       Wecan enter every directory if we have permission -- we talk about permission morea little late. And their has to way to locate a directory.

       Firstcalled absolute pathnames, it's always start with / (root directory), like /usrmean the usr directory belong root directory.

       Secondis called relative pathnames, there is something you must understand is theonly period(.) mean the current working directory ,and double period(..) meanthe parent directory of the current working directory . The relative pathnamesis begin from current directory, like  "./cpp"mean the the directory belong the current working directory.

   We can ignore the ./ always -- "cpp" is equals "./cpp",and "../cpp" mean the cpp directory belong parent directory.

       Thenwe can use the cd command happily,

       cd/usr/bin  # cd the directory named bin belongthe usr directory,and usr is belong the root directory.

       cdcpp/main

       cd..        # cd the parent directory ofcurrent working directory

       andso on.

 

       InTable 2-1 we see some useful ways the current working directory can be quicklychanged.

Shortcut

Result

cd

Changes the working directory to your home directory

cd ~

Changes the working directory to the previous working directory

cd ~username

Changes the working directory to the home directory of username.For example ,cd _bob changes the directory to the home directory of user bob.

 

       Nowwe can climb the Linux filesystem tree.

------------------------------------------------------------------End-------------------------------------------------
内容概要:文章详细介绍了电梯门禁(梯控)系统的硬件安装与接线要点。首先强调了梯控板与楼层按键对接的重要性,包括遵循一一对应原则以避免错层、越层问题,允许空层存在以适应实际需求。接着阐述了不同接线方式(COM、NO、NC端口的不同组合)对用户权限的影响,如单层权限用户刷卡直达指定楼层,多层权限用户在特定接线方式下的操作限制。硬件安装方面,强调了无源干触点设计原则以确保电气隔离,防止系统间干扰,以及读卡器接入时的规范要求。文章还介绍了梯控系统的技术原理,如身份验证机制(二维码/IC卡/人脸识别)、消防联动功能(紧急情况下释放所有楼层权限),并指出该系统适用于小区、写字楼等场景,支持机器人乘梯SDK扩展。最后,根据不同场景需求提出了适用的接线方式选择,如严格管控场景下选择4.3接线以实现精准权限控制,限制多层用户手动选层场景下选择4.1接线并配合软件权限设置。; 适合人群:从事电梯安装维护的技术人员、楼宇自动化工程师及相关领域的管理人员。; 使用场景及目标:①指导技术人员正确安装和接线梯控系统,确保系统安全稳定运行;②帮助管理人员了解不同接线方式对用户权限的影响,以便根据实际需求选择合适的配置方案;③提升楼宇安全管理和服务质量,特别是在小区、写字楼等场所的应用。; 其他说明:梯控系统的正确安装和接线不仅关系到系统的正常运作,更直接影响到用户的安全和使用体验。因此,在实际操作中务必严格按照规范执行,同时关注最新的技术发展和应用场景变化,以确保系统始终处于最佳状态。
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