Shell Scripting: Expert Recipes for Linux, Bash, and More

Chapter 7

Variables Continued

Variables exist in virtually every programming language; without them, there is not a lot a program can do other than simply execute a sequence of commands. With variables in a language, programs can store data that enables them to loop through iterations, take user input, and do different things depending on the values of the variables. This chapter covers in more depth what the bash shell in particular can do with variables; the standard Bourne shell was quite limited in what it could do, but bash and other shells have moved things forward a long way.