Purpose of each of directory:
• /bin – All Core operating system commands [UNIX & Linux]
• /boot – Kernel and files needed to load the kernel [Linux & Solaris]
• /dev – Device entries for disks, printers, pseudo-terminals, etc. [UNIX & Linux]
• /etc – Critical startup and configuration files [UNIX & Linux]
• /home – Default home directories for users [UNIX & Linux]
• /kernel – Kernel components [Solaris]
• /lib – Libraries, shared libraries, and parts of the C compiler [UNIX & Linux]
• /media – Mount points for filesystems on removable media [Linux & Solaris]
• /mnt – Temporary mount points, mounts for removable media [Linux, Solaris, AIX]
• /opt – Optional software packages (not consistently used) [UNIX & Linux]
• /proc – Information about all running processes [Linux, Solaris, AIX]
• /root – Home directory of the superuser (often just /) [Linux & Solaris]
• /sbin – Commands needed for minimal system operabilityc [UNIX & Linux]
• /stand – Stand-alone utilities, disk formatters, diagnostics, etc. [HP-UX]
• /tmp – Temporary files that may disappear between reboots [UNIX & Linux]
• /usr – Hierarchy of secondary files and commands [UNIX & Linux]
• /usr/bin – Most commands and executable files [UNIX & Linux]
• /usr/include – Header files for compiling C programs [UNIX & Linux]
• /usr/lib – Libraries; also, support files for standard programs [UNIX & Linux]
• /usr/lib64 – 64-bit libraries on 64-bit Linux distributions [Linux]
• /usr/local – Software you write or install; mirrors structure of /usr [UNIX & Linux]
• /usr/sbin – Less essential commands for administration and repair [UNIX & Linux]
• /usr/share – Items that might be common to multiple systems [UNIX & Linux]
• /usr/share/man – On-line manual pages [UNIX & Linux]
• /usr/src – Source code for nonlocal software (not widely used) [Linux, Solaris, AIX]
• /usr/tmp – More temporary space (preserved between reboots) [UNIX & Linux]
• /var – System specific data and configuration files [UNIX & Linux]
• /var/adm – Varies: logs, setup records, strange administrative bits [UNIX & Linux]
• /var/log – Various system log files [Linux, Solaris, AIX]
• /var/spool – Spooling directories for printers, mail, etc. [UNIX & Linux]
• /var/tmp – More temporary space (preserved between reboots) [UNIX & Linux]
