Learn Linux Shell Scripting - Fundamentals of Bash 4.4

Variable scopes

While functions are great, there are some things we have previously learned that we'll need to reconsider in the scope of functions, most notably variables. We know that variables store information that can be accessed or mutated multiple times and at multiple points in our scripts. However, something we have not yet learned is that a variable always has a scope. By default, variables are scoped globally, which means they can be used throughout the script at any point. With the introduction of functions also comes a new scope: local. Local variables are defined within a function and live and die with the function call. Let's see this in action:

reader@ubuntu:~/scripts/chapter_13$ vim functions-and-variables.shreader@ubuntu:~/scripts/chapter_13$ ...