Common OS files

Location	Description
/etc/issue	contains a message or system identification to be printed before the login prompt.
/etc/profile	controls system-wide default variables, such as Export variables, File creation mask (umask), Terminal types, Mail messages to indicate when new mail has arrived
/proc/version	specifies the version of the Linux kernel
/proc/[0-9]/fd/[0-9]	contains file descriptors for all processes (first number is the PID, second is the filedescriptor)
/proc/self/environ	contains the environment variables for the current process
/proc/cmdline	contains the kernel boot parameters
/etc/group	contains all the groups that are available on the system
/etc/hosts	contains the IP address to hostname mappings
/etc/passwd	has all registered user that has access to a system
/etc/shadow	contains information about the system's users' passwords
/etc/motd	contains the message of the day, which is displayed to all users after logging in
/etc/mysql/my.cnf	contains the MySQL database configuration file
/root/.bash_history	contains the history commands for root user
/var/log/dmessage	contains global system messages, including the messages that are logged during system startup
/var/mail/root	all emails for root user
/root/.ssh/id_rsa	Private SSH keys for a root or any known valid user on the server
/var/log/apache2/access.log	the accessed requests for Apache webserver
C:\boot.ini	contains the boot options for computers with BIOS firmware