Linux filesystem structure is not imposed by the system. filesystem structure in linux Can vary from one system to the other, even between two GNU/Linux installations!
|/bin/||Basic, essential system commands|
|/boot/||Kernel images, initrd and configuration files|
|/dev/||Files representing devices. /dev/hda: first IDE hard disk|
|/etc/||System configuration files|
|/lib/||Basic system shared libraries|
|/lost+found||Corrupt files the system tried to recover|
Mount points for removable media:
$ /media/usbdisk $ /media/cdrom
|/mnt/||Mount points for temporarily mounted filesystems|
|/opt/||Specific tools installed by the sysadmin.
/usr/local/often used instead
Access to system information.
$ /proc/cpuinfo $ /proc/version $ ...
|/root/||root user home directory|
|/sys/||System and device controls (cpu frequency, device power, etc.)|
Regular user tools (not essential to the system)
$ /usr/bin/ $ /usr/lib/ $ /usr/sbin $ ...
|/usr/local/||Specific software installed by the sysadmin (often preferred to /opt/)|
Data used by the system or system servers
$ /var/log/ $ /var/spool/mail(incoming mail)
$ /var/spool/lpd(print jobs)...
The Unix filesystem structure is defined by the Filesystem Hierarchy Standard (FHS)