2. Linux Directory Structure (File System Structure)

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  1. / – Root
    • Every single file and directory starts from the root directory.
    • Only root user has write privilege under this directory.
    • Please note that /root is root user’s home directory, which is not same as /.

  2. /bin – User Binaries
    • Contains binary executables.
    • Common linux commands you need to use in single-user modes are located under this directory.
    • Commands used by all the users of the system are located here.
    • For example: ps, ls, ping, grep, cp.

  3. /sbin – System Binaries
    • Just like /bin, /sbin also contains binary executables.
    • But, the linux commands located under this directory are used typically by system aministrator, for system maintenance purpose.
    • For example: iptables, reboot, fdisk, ifconfig, swapon

  4. /etc – Configuration Files
    • Contains configuration files required by all programs.
    • This also contains startup and shutdown shell scripts used to start/stop individual programs.
    • For example: /etc/resolv.conf, /etc/logrotate.conf

  5. /dev – Device Files
    • Contains device files.
    • These include terminal devices, usb, or any device attached to the system.
    • For example: /dev/tty1, /dev/usbmon0

  6. /proc – Process Information
    • Contains information about system process.
    • This is a pseudo filesystem contains information about running process. For example: /proc/{pid} directory contains information about the process with that particular pid.
    • This is a virtual filesystem with text information about system resources. For example: /proc/uptime

  7. /var – Variable Files

  1. /tmp – Temporary Files
    • Directory that contains temporary files created by system and users.
    • Files under this directory are deleted when system is rebooted.

  2. /usr – User Programs
    • Contains binaries, libraries, documentation, and source-code for second level programs.
    • /usr/bin contains binary files for user programs. If you can’t find a user binary under /bin, look under /usr/bin. For example: at, awk, cc, less, scp

    • /usr/sbin contains binary files for system administrators. If you can’t find a system binary under /sbin, look under /usr/sbin. For example: atd, cron, sshd, useradd, userdel

    • /usr/lib contains libraries for /usr/bin and /usr/sbin

    • /usr/local contains users programs that you install from source. For example, when you install apache from source, it goes under /usr/local/apache2

  3. /home – Home Directories
    • Home directories for all users to store their personal files.
    • For example: /home/john, /home/nikita

  4. /boot – Boot Loader Files
    • Contains boot loader related files.
    • Kernel initrd, vmlinux, grub files are located under /boot
    • For example: initrd.img-2.6.32-24-generic, vmlinuz-2.6.32-24-generic

  5. /lib – System Libraries
    • Contains library files that supports the binaries located under /bin and /sbin
    • Library filenames are either ld* or lib*.so.*
    • For example: ld-2.11.1.so, libncurses.so.5.7

  6. /opt – Optional add-on Applications
    • opt stands for optional.
    • Contains add-on applications from individual vendors.
    • add-on applications should be installed under either /opt/ or /opt/ sub-directory.

  7. /mnt – Mount Directory
    • Temporary mount directory where sysadmins can mount filesystems.

  8. /media – Removable Media Devices
    • Temporary mount directory for removable devices.
    • For examples, /media/cdrom for CD-ROM; /media/floppy for floppy drives; /media/cdrecorder for CD writer

  9. /srv – Service Data
    • srv stands for service.
    • Contains server specific services related data.
    • For example, /srv/cvs contains CVS related data.