The Linux Filesystem

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The Linux Filesystem has many Folders you will bump into a lot, so it's good to know what each of them is meant for and what they are used for. This Knowledge will help you during the analysis of any Unix system.

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Linux folders explained

• /bin/: basic programs
• /boot/: Linux kernel and other files required for its early boot process
• /dev/: device files
• /etc/: configuration files
• /home/: user's personal files
• /lib/: basic libraries
• /media/: mount points for removable devices (CD/DVD-ROM, USB keys, and so on)
• /mnt/ or /mount/: temporary mount point
• /opt/: extra applications provided by third parties
• /root/: administrator's (root's) personal files
• /run/: volatile runtime data that does not persist across reboots (not yet included in the FHS)
• /sbin/: system programs
• /srv/: data used by servers hosted on this system
• /tmp/: temporary files (this directory is often emptied at boot)
• /usr/: applications (this directory is further subdivided into bin, sbin, lib according to the same logic as the root directory). Furthermore, /usr/share/ contains architecture-independent data. The /usr/local/ directory is meant to be used by the administrator for installing applications manually without overwriting files handled by the packaging system (dpkg).
• /var/: variable data handled by services. This includes log files, queues, spools, and caches.
• /proc/ and /sys/ are specific to the Linux kernel (and not part of the FHS). The kernel uses them for exporting data to userspace.