How to use Linux echo command

Linux dis­tri­bu­tions allow you to set up and control the system yourself. In this context, the bash echo command belongs to one of the most used commands. It is used in bash scripts and batch files to output a status text in a file or on your screen. We explain how the Linux echo command works and how, for example, colours for font and back­ground can be de­term­ined with it.

The Linux echo command repeats what you have told it to repeat. The function is extremely simple, but required to do just that. For example, without echo, you would not get visible output from shell scripts. Shell is the user interface where you can enter different commands, such as the Linux tail command, the Linux head command, the Linux cat command or else the Linux echo command.

How exactly does the Linux echo command work and what is its syntax? Here is an example of the general syntax of the command:

The basic operation of echo is the same in all pro­gram­ming languages. You make an input – which in most cases is in the form of a string – and this is received and output again unchanged.

In our first example, we want to output a text and the contents of variables in bash and terminal, re­spect­ively. To write the text ‘This is an example’, enter the following code into the terminal:

To avoid errors as much as possible, we recommend that you enclose the text in quotation marks:

In the next step we want to output a variable. Here it is enough to enter the name of the variable, such as PWD (for Print Working Directory or your working directory). The command would then look like this:

Then there is also the pos­sib­il­ity to combine the output of variables with text, as in this example:

Once you have un­der­stood the basic principle of the Linux echo command, the next step is to learn which control char­ac­ters you can use in com­bin­a­tion with the command. Control char­ac­ters are char­ac­ters that are not directly visible on the screen, but determine things like the beginning of text, the end of text, or line breaks.

Attention! Echo un­der­stands control char­ac­ters only if you set the -e option. In the following example, ‘\n’ is therefore mapped as text only. (The control character ‘\n’ signals newline or a text wrap).

However, if you add -e, as in the following example, a text break happens in your text:

Here is an overview of which control char­ac­ters are available to you in bash:

The Linux echo command can also be used to specify text at­trib­utes such as colours for the font and back­ground when out­put­ting text. This works by enclosing all char­ac­ters in quotes, or by writing the colours in variables right away to make the string more readable. The first variant looks as follows (a colour is always in­tro­duced with \033[, 31m here stands for the font colour red):

Now to reset all at­trib­utes, enter this string:

However, it becomes more readable if you define colours as variables in your bash script be­fore­hand:

You can simply use the colour as an echo command name:

Below is an overview of the different escape codes for the different font and back­ground colours:

In addition to the colour of the font and back­ground, the Linux echo command can also be used to specify text at­trib­utes such as boldface or underline. Here are the codes for various text prop­er­ties:

If you now want to write the red text in bold, the code is as follows: