Learn Bash Scripting

The if-else statement is the way to make decisions in Bash scripting. In this guide, you will learn how to use if else as part of your scripts. The Bash if-else statement is a conditional statement used in Bash scripting to execute different parts of your script based on the result of the if condition. … Read more

The first time I saw the error “Bash Unary Operator Expected” in the Linux terminal I thought: “And now? What do I do?” 😀 We will understand this error together and we will find a solution for it. The Bash Unary Operator Expected error occurs when Bash identifies a line in your script that contains … Read more

In this article you will learn how to create a while loop in Bash. While loops are used in Bash scripting and in many other programming languages… Let’s create a loop that goes through N numbers and prints only the odd ones. You will see how our script looks like if we hardcode the value … Read more

The Bash bad substitution error is a syntax error that can be caused by different reasons. Two common causes for this error are the incorrect use of command substitution and incorrect characters added to the lines of your script, for example extra dollar signs or white spaces. For example, this error occurs when you want … Read more

Are you seeing the syntax error “unexpected end of file” while executing a Bash script? Let’s find out the cause of this error and how to fix it. When executing a Bash script you might see the error “syntax error: unexpected end of file” if you have created your script using Windows. That’s because Windows … Read more

Bash has several internal variables and in this article we will look at the variable $$. What does this variable mean? How can you use it? $$ is a Bash internal variable that contains the Process ID (PID) of the shell running your script. Sometimes the $$ variable gets confused with the variable $BASHPID that … Read more

If you are working with Linux at some point you will likely start writing Bash scripts. The more your code will grow the more you will realise how useful Bash functions can be. What is a Bash function? Functions are used in Bash scripts, as in other programming languages, to group code in a simpler … Read more

The Bash array data type gives you a lot of flexibility in the creation of your shell scripts. Bash provides two types of arrays: indexed arrays and associative arrays. Indexed arrays are standard arrays in which every element is identified by a numeric index. In associative arrays every element is a key-value pair (similarly to … Read more

Knowing how to replace a string in a file helps if you want to create Bash scripts to automate the configuration of systems or applications. To replace a string in a file using a Bash script you can use the sed command. The sed command allows to perform text manipulation and it can be called … Read more

One of the basic things required in Bash is detecting the number of arguments passed to a script. The reason behind that is being able to modify the behaviour of your script depending on the value and on the number of arguments passed to it. How do you find the number of arguments in Bash? … Read more