/ :- The root of overall file system. The starting directory of unix directory structure. /bin :- It contains all the standard system commands like ls, cp, rm etc. /dev :-This directory contains logical device names. /etc :- This directory contains configuration files. /home :- Home directory for users. /export :- The default directory for shared file system's. eg;- User's home directories and other shared file systems. /kernel :- This contains kernel files that are required as part of the booting process. /lib :- The contents of this directory are shared executable files that are used by many applications at the same time. Library files are part of executables (these are also executables) so that you don't have to write same code again and again. /mnt :- A temporary mount point for external file systems. /opt :- Directory used for installation of external software's and applications. /sbin :- This directory contains files that are used by system during booting process. it contains system specific commands. The executables in this directory are very important and are user during system failure. /usr :- Programs and files or executables available for normal system users. Basically /usr/bin and /bin are symbolic links to each other. /var :- Directory for saving system and admin logs. we call it var directory because it contains files that vary from time and time and by that we mean log files. All system administration logs are under var directory. /devices :- the primary directory for physical device names. /proc :- stores current process related information. all the processes currently running have directories and subdirectories in this directory. these directories are named with the PID of the process. /tmp :- This directory is used to store temporary files. This directory gets cleared if system is down.
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