Command-Line Rust

Chapter 7. Finders Keepers

Then / Is when I maybe should have wrote it down / But when I looked around to find a pen / And then I tried to think of what you said / We broke in two

They Might be Giants, “Broke in Two” (2004)

In this chapter, you will write a Rust version of the find utility, which will, unsurprisingly, find files and directories for you. If you run find with no restrictions, it will recursively search one or more paths for entries such as files, symbolic links, sockets, and directories. You can add myriad matching restrictions, such as for names, file sizes, file types, modification times, permissions, and more. The challenge program will locate files, directories, or links in one or more directories having names that match one or more regular expressions, or patterns of text.

You will learn how to do the following:

• Use clap to constrain possible values for command-line arguments

• Use a regular expression to find a pattern of text

• Create an enumerated type with an implementation

• Recursively search filepaths using the walkdir crate

• Use the Iterator::any function

• Chain multiple filter, map, and filter_map operations

• Compile code conditionally when on Windows or not

• Refactor code

How find Works

Let’s begin by exploring what find can do by consulting the manual page, which goes on for about 500 lines detailing dozens of options. The challenge program for this chapter will be required to find entries in one or more paths, and these entries can ...