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Beginner · урок 02·~15 мин
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About

The directory tree: /etc, /proc, /sys, /var and the rest

The Linux directory tree is not a dump but a standard, the fhs (Filesystem Hierarchy Standard): each top-level directory has its own meaning. Once you know the map, you immediately know where to put a config, where to look for logs, and where to read kernel state.

In this lesson you walk through the main directories by hand: /etc (configs), /proc and /sys (virtual windows into the kernel, with nothing on disk), /dev (device files), /var, /run, /tmp, /usr. After it, ls / stops being a row of cryptic letters.

Если уже знаком с темой, пропустить введение и сразу к терминалу.

What you'll learn

Что узнаешь

Ключевые идеи урока. Каждая разбирается на отдельном шаге с проверкой.

  • ┌FHS fixes a meaning for each root directory: a standard, not a habit
  • ├/proc and /sys are virtual file systems: files are generated by the kernel on the fly, not stored on disk
  • ├/etc holds configs (back them up), /usr reinstalls from the repo, /var holds large changing data
  • ├/run and often /tmp are tmpfs in RAM: the contents vanish on reboot
  • └In /dev, devices appear as files: /dev/null swallows input, /dev/zero hands out zeros
Commands

Команды, которые встретятся

Не нужно их заучивать заранее, запомнятся по ходу. Беглый взгляд сейчас сделает урок легче.

командачто делает
ls -la /all top-level directories of your system
cat /etc/os-releasewhich distribution and version this is
cat /proc/cpuinfo /proc/meminfoCPU and memory as the kernel sees them
ls /sys/class/netnetwork interfaces as sysfs objects
df -h /run /tmpsee that /run (and often /tmp) is tmpfs in RAM
command -v <bin>which PATH directory holds a binary
Knowledge base

База знаний по теме

Короткие справочные статьи. Не главы, не нужно читать перед уроком. Удобно открывать после, чтобы закрепить термин.

/kb/process-and-pid

Processes and /proc/<pid>

/kb/cgroups

cgroups: CPU and memory limits

/kb/cmd-sysctl

sysctl and /proc/sys

/kb/fhs

Filesystem Hierarchy Standard

/kb/tmpfs-overlayfs

tmpfs and overlayfs

готов?

Sandbox запустится автоматически, подожди 5–10 секунд после клика.

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