The Kernel
The Kernel of Linux is like the core of the operating system. It has a direct link to the HAL of Linux (which is managed by lower-level device drivers and even BIOS) and is initialized by the bootstrap process, initd. The kernel sets the rules governing fair use of hardware resources, memory, and the file system by delegating these respective areas to other, specialized programs. The kernel can also be considered the “engine” of Linux, because without it, you do not have Linux. However, the kernel is not anything huge or special. Actually, it is quite small, and does little of the work itself. Rather, it is more of a moderator between applications, other applications, and hardware.
Remember, binaries in Linux are different than those in Windows. Therefore, you cannot use EXE files from Windows (or other programs) in Linux. That is, without a special tool that I will describe in the next tutorial.
BASH (Shell)
If you are familiar with Windows, you have probably seen or used a DOS-style prompt in your life. Perhaps you remember tinkering around with commands. With Linux, because choice is a core concept, you may choose what type of prompt you wish to use. However, most distros use BASH because it is well developed, open-source, and stable. BASH converts what you type into what the kernel can understand. BASH in analogous to an interpreter between an obnoxious American (the user) and a well-cultured Frenchman (the kernel). A BASH prompt looks like this:
[Sheneanae@Localhost /]$ user enters commands here
The bold face is where you enter commands. The dollar sign is often known as the shell sign because it always comes before your commands. To run a binary (an executable), let’s say the popular program nmap, you need to type something like this:
[Sheneanae@Localhost /]$ ./nmap
The dot slash signifies in Linux that you are operating within that particular folder. It is something that Windows users often forget to use. Many times, people will simply type in something like:
[Sheneanae@Localhost /]$ nmap
This is not the same as the above. Now, you are either referencing a BASH command or a /bin program. Notice that BASH commands do not need the dot slash because the dot slash signifies that you are operating within the current folder, and BASH operates universally. Also, programs within the /bin directory do not need a dot slash because they are put in that folder to be universally executable. If you are a real Windows addict, you may equate the /bin folder in Linux to the C:WindowsSystem32 folder in Windows.
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