It's amazing how much there is to know about files without ever opening them. But all the cataloging and organizing and finding of files is simply a prelude to using them-and that usually means dealing with what's inside.
Chapter 25, Showing What's in a File talks about various ways to dump the entire contents of a file to your screen-all at once, or in manageable pieces.
Chapter 26, Regular Expressions (Pattern Matching) describes the essential prelude to any more precise look at just parts of a file-the regular expressions that allow you to match textual patterns rather than fixed words or phrases.
Chapter 27, Searching Through Files describes the grep family of programs, which use regular expressions to find and print individual matching lines from a file or files. grep is the program that people ignorant of UNIX like to pick on for its seemingly obscure name, yet it is one of the handiest tools UNIX provides.
Chapter 28, Comparing Files tells how to compare two files that might have a great deal in common, how to isolate the differences, and how to put Humpty back together again when versions have become skewed with multiple incompatible edits.
Chapter 29, Spell Checking, Word Counting, and Textual Analysis describes some specialized ways to look at files-spell checking, word counting, and various kinds of simple proofreading.
Chapter 25: Showing What's in a File
Chapter 26: Regular Expressions (Pattern Matching)
Chapter 27: Searching Through Files
Chapter 28: Comparing Files
Chapter 29: Spell Checking, Word Counting, and Textual Analysis