Linux Shell

If you are using a debian based Linux distribution like I am, then the shell you are using whats called BASH or “Bourne Again SHell”, which is a GNU project created by Brian Fox. Another amazing human being. If you ever happen to read this blog Brian, thank you. To interact with the shell we use another program called a terminal emulator, which in my case is alacritty (thanks to rwxrob for showing me and the 276 current people working on it). To open the terminal emulator you can use the shortcut ctrl + alt + t. An interesting note that the book makes is that if the last character of the shell prompt is a # sign rather than a $ sign, then the session has superuser privileges. Only two pages into the first chapter and already learning something new.

If we have already typed commands into the shell prompt then we will have access to the command history which is accessible via the up-arrow and down-arrow keys. The book states that even the mouse is capable of interacting with the terminal emulator via the X Window System. If you highlight text by holding down the left mouse button and dragging the mouse over it (or double clicking a word), it is copied into a buffer maintained by X. This can then be pasted with the middle mouse button. Wow. I’ve always used ctrl + shift + c/v with the highlighted text, I never realized it was copied when it’s highlighted, nor that you can paste with middle mouse button.

Now for some basic commands. The first is date, which as you might guess, displays the current datetime. The second is cal which displays a calendar. The third is df which shows the amount of free space on the disk drives. The fourth is free which displays the amount of free memory. Of these, the only one I knew about is df, which I use with the -h flag to make the output human readable. To end the terminal session you can either type exit or enter the shortcut (which I never knew about until now) ctrl + d.

I want to just give a tip to anyone who might be like me and be too eager to try things before reading something entirely. Don’t. Read the entire section before doing something or you will end up in panic mode like I just was cause I executed ctrl + alt + f1 and entered into a virtual terminal without knowing how to get back to the graphical desktop (alt + f7). There are up to six virtual terminals accessible via ctrl + alt + f1-6.

Already learning so much and that was only from the first chapter!