To make your time in the shell more productive, you have shell variables at your disposal. Shell variables are names that hold values. A value can be a path name, a filename, or maybe a number, the shell treats any assignment as a string of text.
There are two types of variables, local and environment. Strictly speaking there are four, but the other two are read-only and are considered special variables used in passing parameters to shell scripts.
In this chapter we will cover:
passing information to scripts; and
using positional parameters on system commands.