Learn Bash Scripting

Sometimes while writing a Bash script I have seen the Bad substitution syntax error and looking at forums I realised that I’m not alone, other people are seeing the same error too. What is the Bash bad substitution error? It’s a syntax error that occurs when you execute your Bash script and it can be … 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

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. What is the Bash Unary Operator Expected error? It’s an error that occurs when Bash identifies a line … Read more

The export command is a built-in command of the Bash shell that is very handy to know when you work on Linux systems or create Bash scripts. What does the export command do in Linux? The export command is used to make variables or functions in the current shell environment also available to child processes … Read more

Have you ever seen the message “syntax error near unexpected token” while running one of your Bash scripts? In this guide, I will show you why this error occurs and how to fix it. “Error Near Unexpected Token” is a Bash syntax error that reports bad syntax in your script or command. Many things can … Read more