/proc is very special in that it is a virtual filesystem. It’s sometimes referred to as a process information pseudo-file system. It doesn’t contain ‘real’ files but runtime system information (e.g. system memory, devices mounted, hardware configuration, etc).Inside the /proc directory, you’ll see two types of content — numbered directories, and system information files. /proc is not a real file system, it is a virtual file system. For example, if you do ls -l /proc/stat, you’ll notice that it has a size of 0 bytes, but if you do “cat /proc/stat”, you’ll see some content inside the file.For this reason it can be regarded as a control and information centre for the kernel. In fact, quite a lot of system utilities are simply calls to files in this directory. For example, ‘lsmod’ is the same as ‘cat /proc/modules’ while ‘lspci’ is a synonym for ‘cat /proc/pci’. By altering files located in this directory you can even read/change kernel parameters (sysctl) while the system is running.
