This is a C++ implementation of the "Build Your Own grep" Challenge.

Features

This grep implementation supports the following regular expression features:

• Literal characters: a, b, 1, 2, etc.
• Digits: \\d
• Word characters: \\w
• Positive Character Groups: [abc]
• Negative Character Groups: [^abc]
• Start of string anchor: ^
• End of string anchor: $
• One or more times: +
• Zero or one times: ?
• Wildcard: .
• Alternation: |
• Backreferences: \\1, \\2, etc.

Usage

Building the project

1. Ensure you have cmake installed locally.
2. Run cmake . to generate build files.
3. Run make to compile the project.
4. The executable will be named exe.

Searching from stdin

To search from standard input, provide the -E flag and a pattern:

echo "hello world" | ./exe -E "world"

Searching a single file

To search a single file, provide the file path after the pattern:

./exe -E "pattern" file.txt

Searching multiple files

To search multiple files, provide the file paths after the pattern:

./exe -E "pattern" file1.txt file2.txt

Recursive search

To perform a recursive search in a directory, provide the directory path:

./exe -E "pattern" my_directory/

Development

The main entry point is in src/Server.cpp. The pattern matching logic is implemented in src/pattern_matcher.cpp and src/pattern_matcher.h.