Search Utility

In this programming assignment, you are expected to implement a command-line utility that searches for a specific string in one or multiple files, similar in spirit to the UNIX grep command. This assignment will help you practice command-line argument parsing, working with external crates as dependencies, and using file I/O in Rust. The assignment is due at 11:59 p.m. on Monday, October 20, 2025.

Foundation: Basic Search

As a starting point, your command-line utility should accept a string, such as a simple string, and one file (possibly also including its path) as command-line arguments. It should then search for the given string in the specified file(s) and print the lines that contain the string. For example, if you run your utility with the command (where target/debug/grep is your compiled executable):

$ cargo build
$ target/debug/grep Utility tests/grep.md

In this example, assume that the file tests/grep.md contains:

## Search Utility
In this programming assignment, you are expected to implement a command-line utility that
searches for a specific pattern in one or multiple files, similar in spirit to the UNIX
`grep` command.

It should output:

## Search Utility

If the string to be searched is not found, the output should be empty.

Now that the basic functionality has been built, we should start adding more features to our utility. Here are some of the features you should implement:

$ target/debug/grep Utility tests/*.md

$ target/debug/grep Utility tests/grep.md ../README.md

$ target/debug/grep -h

Usage: grep [OPTIONS] <pattern> <files...>

Options:
-i                Case-insensitive search
-n                Print line numbers
-v                Invert match (exclude lines that match the pattern)
-r                Recursive directory search
-f                Print filenames
-c                Enable colored output
-h, --help        Show help information

$ target/debug/grep Utility tests/grep.md -i

## Search Utility
In this programming assignment, you are expected to implement a command-line utility that

$ target/debug/grep Utility tests/grep.md -n

1: ## Search Utility

$ target/debug/grep Utility tests/grep.md -v

In this programming assignment, you are expected to implement a command-line utility that
searches for a specific pattern in one or multiple files, similar in spirit to the UNIX
`grep` command.

$ target/debug/grep Utility tests -r

$ target/debug/grep Utility tests -r

## Search Utility
## Search Utility

$ target/debug/grep Utility tests -r -f

tests/recursive/grep.md: ## Search Utility
tests/grep.md: ## Search Utility

$ target/debug/grep Utility tests -r -c -f

tests/recursive/grep.md: ## Search Utility
tests/grep.md: ## Search Utility

Implementation Notes

You may wish to use a Config struct to store search configuration after parsing the command-line arguments.

Use the external crates colored and walkdir to implement the -c and -r options, respectively. To use these crates, you should first add these crates to your Cargo.toml file.

There is no need to handle any errors in this assignment. You can assume that the user will provide the correct command-line arguments, and that there are no binary files that are not UTF-8 encoded in the directories you are searching. It is fine to panic at run-time if such errors occur.

When you start to work on your assignment, make sure you use the command cargo new to create a new project, including a Cargo.toml file and a src/main.rs file, as well as an initial git repository. Take advantage of the git repository that cargo new creates for you, and push your local commits to GitHub. Once your project is managed by git, you can then start writing your code in the src/main.rs file. Of course, you can also create additional files in the src directory if you need to. You can compile and run your code using the cargo run command, as we have introduced in our lectures.

Testing

Consider the following directory structure, mentioned previously:

Test the following cases:

cargo run -- -h

Usage: grep [OPTIONS] <pattern> <files...>

Options:
-i                Case-insensitive search
-n                Print line numbers
-v                Invert match (exclude lines that match the pattern)
-r                Recursive directory search
-f                Print filenames
-c                Enable colored output
-h, --help        Show help information

cargo run -- Utility tests/grep.md

## Search Utility

cargo run -- Utility tests/grep.md tests/recursive/grep.md

## Search Utility
## Search Utility

$ cargo run -- Utility tests/*.md tests/recursive/*.md

## Search Utility
## Search Utility

$ cargo run -- Utility tests/grep.md -i
$ cargo run -- Utility tests/grep.md -n
$ cargo run -- Utility tests/grep.md -v
$ cargo run -- Utility tests -r
$ cargo run -- Utility tests -r -f
$ cargo run -- Utility tests -r -c -f

For your convenience, an initial set of 10 test cases has been released to you as a compressed archive, named a2-public-tests.tar.gz, and reflecting what you can find in this section. Run the command tar zxvf a2-public-tests.tar.gz to uncompress the archive to a directory, and then move the content of the archive to your source code directory that you created using cargo new, so that cargo run works successfully. You can use these test cases to test your implementation against the expected output, and revise minor output differences as necessary. To run the test, you can use the following command:

bash input.sh > my_output.txt

To compare the output of your program with the expected output, you can use the diff command:

diff my_output.txt output.txt

Notes on AI Tools

This assignment is designed for manual work without AI assistance, and you should not use AI tools at all for this assignment. While we recognize that the habit of using AI may be so reflective and strong that — like social media — you cannot think without AI assistance, you need to learn coding in the Rust programming language and this learning experience needs to start from somewhere. Similar to the previous assignment on the Reversi board game, this assignment offers a sufficiently simple canvas for you to continue your learning experience and to expand your set of skills in Rust, and using AI defeats the purpose and completely changes the learning experience. Heed our advice: do not use AI and you will enjoy such “raw” coding experience much more.

Submission

Submit your project by submitting a .tar.gz archive of it using Quercus, under Assignment 2. Use the following command to create your .tar.gz archive:

cd /path/to/parent/directory
tar zcvf 1234567890.tar.gz project_directory

where 1234567890 is your student number, and project_directory is the name of the directory containing your project files, such as grep. This is also the project name you initially provided to the cargo new command. Make sure that your archive contains all the files necessary to build and run your project, including the Cargo.toml file and the src directory as shown above. Also, make sure that your project builds and runs correctly after extracted from the archive, using the cargo run command.

Marking

Your project will be built and tested using the cargo run -- command against a set of 20 test cases¹, including 10 public test cases that are released to you, and 10 more hidden test cases that we use internally for testing your solutions. The marking will be based on the correctness of your implementation in these test cases, by comparing the output of your code to the correct output.

Make sure that your code is well-commented, easy to read, and that you have followed the Rust naming conventions. You should also make sure that your code is free of warnings when compiled with the cargo build or the cargo check command.