greppy

A Rust implementation of a grep-like tool, originally built as a solution for CodeCrafters "Build your own grep" challenge.

Features

• Zero-copy of the testing string,
• UTF-8 support,
• Wildcards,
• Positive/negative char groups,
• Start and end anchors,
• Quantifiers,
• Ranges: a{2}, a{2,4} or a{2,},
• Capture groups & backreferences.

Missing features

• Word boundary: \b,
• Non-classes: \W, \D, \B

Usage

Piping from standard input:

$ echo "123 foo 456 bar 123 baz 456" | cargo run --release -- -E "(\d+).*(\d+).*\1.*\2"

123 foo 456 bar 123 baz 456

From a file:

$ echo "How many yaks could a yak-pack pack if a yak-pack could pack yaks?" > file.txt
$ cargo run --release -- -E "How many ((yak)s) could a (\2-(pack)) \4 if a \3 could \4 \1?" file.txt

file.txt:How many yaks could a yak-pack pack if a yak-pack could pack yaks?

From multiple files/directories (with recursive -r option enabled):

$ mkdir -p dir/subdir
$ echo "🦦 🦦 🦦" > dir/subdir/file.txt
$ echo "🐼 🐼 🐼" > another_file.txt
$ cargo run --release -- -r -E "(.*) \1 \1" dir another_file.txt

dir/subdir/file.txt:🦦 🦦 🦦
another_file.txt:🐼 🐼 🐼

License

Licensed under MIT license (LICENSE or http://opensource.org/licenses/MIT).