Bash Cookbook

Creating and using basic variables

The best way to think of variables is as placeholders for values. They can be permanent (static) or transient (dynamic), and they will have a concept called scope (more on this later). To get ready to use variables, we need to think about the script you just wrote: my_first_script.sh. In the script, we could have easily used variables to contain values that are static (there every time) or dynamic ones created by running commands every time the script is run. For example, if we would like to use a value such as the value of PI (3.14), then we could use a variable like this short script snippet:

PI=3.14echo "The value of PI is $PI"

If included in a full script, the script snippet would output:

The value of ...