cora

Multi-pattern fixed-string matcher. Searches files or stdin for one or more literal patterns using Aho-Corasick. Outputs NDJSON.

Requirements

• Rust 1.70+ (uses edition 2021)

Install

cargo build --release
cp target/release/cora ~/.local/bin/

Usage

cora [OPTIONS] <PATTERNS...> [-- FILES...]

Patterns can be labeled: err=ERROR produces matches tagged with the label err. Without a label, matches use the 0-based pattern index.

Reads from stdin when no files are given.

Options

Flag	Short	Description
--verbose	-v	Full-key NDJSON output
--insensitive	-i	Case-insensitive matching
--context N	-C N	Include N lines before/after each match
--max-matches N	-M N	Stop after N matches (0 = unlimited)
--count	-c	Summary only, no match lines
--pattern-file PATH	-f PATH	Read patterns from file (one per line, label=pattern, # comments)
--describe		Emit JSON capability manifest and exit

Output

Each match is one JSON line. Default mode uses short keys:

Key	Type	Description
p	int	Pattern index (0-based)
n	string?	Pattern label (if provided)
l	int	Line number (1-based)
c	int	Column (1-based)
b	int	Byte offset from start of file/stream
m	string	Matched text
t	string	Full line text
f	string?	File path (omitted for stdin)
cb	string[]?	Context lines before (omitted when empty)
ca	string[]?	Context lines after (omitted when empty)

Both modes are lossless — same fields, different key names. With -v, keys expand:

Tune	Verbose
p	pattern_id
n	label
l	line
c	column
b	byte_offset
m	match
t	text
f	path
cb	context_before
ca	context_after

The last line is always a summary:

{"_":"summary","n":42,"tr":false,"files":{"app.log":{"n":42,"sz":8192}},"pats":{"err":30,"warn":12}}

Examples

# Search stdin
echo 'connection error detected' | cora error warning

# Search files with labeled patterns
cora 'err=ERROR' 'warn=WARN' -- app.log server.log

# Case-insensitive with context
cora -i -C 2 error -- app.log

# Count only
cora -c ERROR WARN -- *.log

# Patterns from file
cora -f patterns.txt -- app.log

# Machine-readable self-description
cora --describe

Dependencies

Crate	Purpose
aho-corasick	Multi-pattern matching
clap	CLI argument parsing
memmap2	Memory-mapped file I/O
memchr	SIMD byte search
itoa	Integer formatting
serde / serde_json	Summary serialization
anyhow	Error handling

License

MIT