Author: Kfjie(None)

The Linux file system uses a tree-like structure, and all files and directories start at Root Directory (/)。

Diagram of the Linux File System Structure

  graph LR
    Root["/ (根目录)"]

    subgraph sg_core [核心系统]
        Usr["/usr/"]
        Boot["/boot/"]
        LinkBin["/bin, /sbin, /lib*"]
    end
    
    LinkBin -.-> Usr
    Root --> Usr
    Root --> Boot

    Usr --> UsrBin["bin/ (git, python3)"]
    Usr --> UsrSbin["sbin/ (nginx)"]
    Usr --> UsrLocal["local/ (手动安装)"]
    Usr --> UsrLib["lib/ (库文件)"]

    subgraph sg_data [配置与数据]
        Etc["/etc/"]
        Var["/var/"]
        Tmp["/tmp/"]
    end

    Root --> Etc
    Root --> Var
    Root --> Tmp

    Etc --> NginxConf["nginx/"]
    Etc --> Systemd["systemd/system/"]
    Etc --> Ssh["ssh/"]

    Var --> Log["log/"]
    Var --> Www["www/"]

    subgraph sg_apps [应用软件]
        Opt["/opt/"]
        Snap["/snap/"]
    end

    Root --> Opt
    Root --> Snap
    
    Opt --> OpenList["openlist/"]

    subgraph sg_users [用户空间]
        Home["/home/"]
        RootHome["/root/"]
    end
    
    Root --> Home
    Root --> RootHome

    subgraph sg_virtual [虚拟文件系统]
        DirProc["/proc/"]
        DirSys["/sys/"]
        DirDev["/dev/"]
        DirRun["/run/"]
    end

    Root --> DirProc
    Root --> DirSys
    Root --> DirDev
    Root --> DirRun

    subgraph sg_mounts [外部存储]
        Mnt["/mnt/"]
        Media["/media/"]
    end

    Root --> Mnt
    Root --> Media

1. Core System Directory

bin & sbin (Binaries)

• Uses : Stores executable commands.
• Note：
  • bin : Contains basic commands that all users can use, such as ls, cp, mv etc.
  • sbin : Contains commands primarily used for system administration; typically, only users with administrator privileges can execute them, such as reboot, fdisk etc.

etc (Etcetera/Configuration)

• Uses : Stores system and software configuration files.
• Note : Nginx configuration, user account information, network configuration, and other items are all located here. Modifying files in this directory will directly affect the behavior of the system or services.
  • For example: My Nginx configuration file is located at /etc/nginx/nginx.conf。

lib, lib64 (Libraries)

• Uses : Stores system shared libraries.
• Note : Similar to Windows .dll Files that provide runtime support for programs in the system.

systemd (System Daemons)

• Key Index：/etc/systemd/system/
• Uses：Housekeeper Headquarters。
• Note : This is where the “service configuration files” are stored (.service (file).
  • When you run systemctl enable nginx or systemctl start frps At that point, the system actually looks here for the corresponding file.
  • docker.service.d/ : Custom configuration directories for Docker services (such as proxy settings).
  • If you want a program to run automatically at startup, you’ll need to place a configuration file here.

boot (Boot Loader)

• Uses : Startup file.
• Note : Store the kernel (vmlinuz) and the boot loader (GRUB). You generally don’t need to change these unless you’re troubleshooting boot issues on this machine.

2. Where is the software located? (Software Locations)

On Linux, software isn’t centralized the way it is on Windows Program Files...but are scattered across different locations depending on how they are installed. Here is the actual situation on my server:

Published on 2026-02-07 at kj’s blog, last modified on 2026-02-07

Author: Kfjie(None)

Server Operations Tips: SSH Tunnels and Docker Network Configuration

This post records how to temporarily use a local proxy through an SSH reverse tunnel when maintaining a remote Linux server, for code downloads, dependency installation, and Docker image pulls.

The examples use the forwarded port 127.0.0.1:7890 on the server, configure network proxies separately for the shell and Docker daemon, and remove the temporary settings when the task is complete.

Published on 2026-02-06 at kj’s blog, last modified on 2026-02-06