- Kernel
- Hardware
- Running Process
All the files under /proc can be viewed by the cat command.
/proc/
These informations used by the commands like ps and top to display the running process
For example, If you run the httpd service and it has 3992 process ID, Its information will be located in /proc/<3992>
Some Important files under /Proc:
/proc/cpuinfo - contains the information about CPU.
/prc/mdstat - contains the information about RAID about md devices (used by mdadm command)
/proc/meminfo and /proc/swaps – Contain the information about memory usage and swap usage (used by free and vmstat commands)
/proc/modules - Contains the list of modules. It can be viewed by the lsmod command.
/proc/mounts contain the mounted file system information
/proc/partitions - Contains the partitions information
/proc/net - contains the information about networking (Used by ifconfig and netstat )
/proc/version - Contains Linux kernel version (uname –v)
/proc/sys/kernel/hostname - contains system hostname
/proc/sys/net/ipv4/ip_forward - You can make IP forwarding ON or OFF by editing this file. the same can be done with sysctl -w as well