The /proc directory is a way to view information on the running processes and the kernel within the file system.
For each process on the computer, there is a directory containing files with information on it.
This is a file that contains the command that started this process.
For example, run ps and get the process id of the shell. Next, run cat /proc/[pid]/cmdline (pid being the shell's process id.) And you would see the command that started the shell (probably bash.)
This is a symlink to the current working directory of the process
Now, run readlink -f /proc/[pid]/cwd with pid still being the process id for the shell, and you will see the directory you are currently in.
This is a symlink to the original executable
And now, run readlink -f /proc/[pid]/exe and you will get the location of bash (or what ever shell you were using).
This contains information on the current version of Linux and its compiling.
This contains how long the kernel has been running for in seconds.
This is just a bit of the information you could get from the /proc directory.
