This chapter provides detailed descriptions of some commonly used shell programming tools. Covered are
sort. The more proficient you become at using these tools, the easier it will be to write efficient shell scripts.
Before getting into the tools, you need to learn about regular expressions. Regular expressions are used by many different Unix commands, including
grep, and, to a more limited extent, the
vi editor. They provide a convenient and consistent way of specifying patterns to be matched.
Where this gets confusing is that the shell recognizes a limited form of regular expressions with filename substitution. Recall that the asterisk (
*) specifies ...