Some directories support the Linux kernel, the lowest-level part of the Linux operating system.
The files in /proc provide views into the running kernel and have special properties. They always appear to be zero sized, read-only, and dated now:
$ ls -l /proc/version -r--r--r-- 1 root root 0 Oct 3 22:55 /proc/version
However, their contents magically contain information about the Linux kernel:
$ cat /proc/version Linux version 2.6.32-71.el6.i686 ...
Files in /proc are used mostly by programs, but feel free to explore them. Here are some examples:
3.149.254.35