Important files on Linux system

linux_important_files

/etc/passwd                     : encrypted password for system users in Linux (relates to /etc/shadow)
/etc/crontab                    : scheduled shell scripts for automatically
/etc/fstab                      : mount point on Linux
/etc/initd/                     : service startup location
/etc/grubconf                   : GRUB bootloader configuration
/etc/inittab                    : Run level mode configuration
/etc/issue                      : Login banner message
/etc/profile                    : Bash shell in default
/etc/sysconfig/network-scripts/ : network configuration
/etc/X11                        : X-window configuration
/etc/resolvconf                 : dns configuration
/etc/hosts                      : IP to host name configuration for local Linux
/usr/sbin                       : commands for System users
/usr/lib                        : Libraries for Compiled package
/usr/share                      : man files
/usr/bin                        : User executable bash commands
/var/log/messages               : main log file on Linux
/var/www/html                   : default web root
/proc/cpuinfo                   : cpu related information
/proc/meminfo                   : memory related information
/etc/selinux/config             : SELinux configuration file
/etc/wgetrc                     : wget config file
/etc/yum.conf                   : yum config file