Operation Manual

The Linux Command Line
153
Notes:
Lesson 6.1: Commands are just programs
When you type into the terminal you are running programs. Most of the commands
listed here run programs that give you the ability to command the system to do
something. When you add programs to your Raspberry Pi, you will be able to run
more commands.
If you enter a command and it doesn’t work, it may well mean that the program
isn’t installed yet. For instance, if you try to create a new text file called “My Linux
Commands” using the Nano text editor, you would type:
sudo nano "My Linux Commands"
But it might be that, instead of opening the new text file, your system returns the
error message:
bash: nano: command not found
This just means that you have not installed Nano yet. However, most of the
commands described on this page are the kind of “housekeeping” commands
that come as default, so you shouldn’t have this problem. Each program has an
original author who is acknowledged at the bottom of the main page.
Don’t worry too much about the actual commands used there – I will explain
everything as we go along.
The Bash shell
To use the CLI, you need to know commands. The default command set is
contained in the “shell” you are using. There are lots of shells out there, but the
one on this Raspberry Pi is called “Bash”. Bash is the default command line shell
on most versions of Linux, as well as Mac OS, so it’s well worth learning.
This chapter covers many of the most common and useful commands. If you can’t
find the command you need, try looking online. There are lots of good guides on
the internet for using the Linux command line.
If you know the command you want to use, but don’t know exactly how to use it
– for instance, you don’t know exactly the right “syntax” – you can use the “man”
(manual) command in Linux. At the command line you could type:
$ man <command>
man
Displays information about the target, sourced from online
reference manuals.
Tip...
The “syntax” of a
command means
the way it should
be written to make
it work. That
means the order
of the words, as
well as any
important
punctuation that is
also necessary.