What is a process?
Processing now…
This is the fourth installment of the series. This time, let’s take a brief look at the Linux processing capabilities.
The process is a program that is currently running on our system. On the other end of the spectrum, a program includes a wide range of meanings, such as data that exist in a file format.
In the following example, hello.c is a program that generates hello processes every time you run the program. Hence, you can generate multiple processes by running a program.
By executing ps -ef command, for example, your system will list all the processes running on it.
ps -ef
As you can see in the following output, there are multiple processes that share the same process name: /usr/sbin/smbd.
Process ID
As I mentioned above, multiple processes have the same process name. So how do we identify them individually? The answer is simple: process id. The process id is an identical (or unique) id that is assigned to every process id running on your system, so none of them is duplicated. In image 02, the column that says PID is the one.
Signal
Ctrl + c, for instance, is a signal. Probably you’ve already used this command a lot on your PC. This is the signal that sends SIGINT to a running process, and the process that receives it will automatically finish its operation. This is something we’ll learn later on. What we need to know is that signal is a system that has been residing in UNIX/Linux system for a long time and is an integral part of it.