Build Your Own wc Tool

This challenge is inspired by the wc command-line tool in Unix-like systems. The wc tool counts the number of words, lines, and characters in a file. By building your own version of wc, you'll learn about file I/O, text processing, and command-line arguments.

Table of Contents

The tools within Linux and Unix-like systems are great examples of good software engineering because they follow the Unix Philosophies of:

• Modularity: Each tool should do one thing well.
• Composability: Tools can be combined to perform more complex tasks.

Following these principles has made the Unix command line tools some of the most widely used software in industry. If you are interested, you can read more about the Unix Philosophy in the book [The Art of Unix Programming](http://www.catb.org/~esr/writings/taoup/html.

The Challenge

Your task is to create a command-line tool that reads a file and outputs the number of words, lines, and characters in that file. The tool should accept the file path as a command-line argument.

You can read more about the functional requirements for wc by reading its man page:

man wc

The TL/DR version of the wc command is -- word, line, character, and byte count.

Supported Arguments

Your tool should support the following command-line arguments:

• -w or --words: Display the word count.
• -l or --lines: Display the line count.
• -c or --characters: Display the character count.
• -m or --bytes: Display the byte count.

Additionally, it should support passing no arguments other than the file path, which should display all counts (words, lines, and characters).

Example Usage

Here's an example of how your tool should work:

# Display word count
$ wc -w file.txt
58164 file.txt

# Display line count
$ wc -l file.txt
1234 file.txt

# Display character count
$ wc -c file.txt
123456 file.txt

# Display byte count
$ wc -m file.txt
123456 file.txt

# Display all counts
$ wc file.txt
1234 58164 123456 file.txt

-m or --bytes Count and Locales

The -m or --bytes option should count the number of bytes in the file. This is different from the character count because it counts the number of bytes in the file, not the number of characters. This is important because different locales have different character encodings, and counting bytes is a more accurate representation of the file size.

You can learn more about programming for locales and character encodings in the book The Unicode Standard and the article Locale and Culture.

Extra Credit

If you want to take this challenge further, consider adding support for being able to read from standard input if no file path is specified.

This would allow you to use your tool in a Unix pipeline like this:

$ cat file.txt | wc -l
1234