Pro Bash Programming : Scripting the GNU/Linux Shell, Second Edition

CHAPTER 4

Command-Line Parsing and Expansion

One of the strengths of the shell as a programming language is its parsing of command-line arguments and the various expansions it performs on words in the line. When a command is called with arguments, the shell does several things before it invokes the command.

To help visualize what happens, the short script shown in Listing 4-1, called ba, will display what the shell has passed to it after processing all the arguments. Each of its arguments is printed on a separate line, preceded by the value of $pre and followed by the value of $post.

Listing 4-1. ba; Displaying Command-Line Arguments

pre=:post=: ...