outmatch

Output matching for shell commands. A modern replacement for Cram with a cleaner interface, dynamic test generation, multiple tests per file, and zero dependencies.

Write a test — just a command and its expected output:

Run it:

When something breaks, you get a clear diff:

Fix it automatically — outmatch rewrites expected output in-place:

Install

pip install outmatch

Or with uv:

uv tool install outmatch

CLI

outmatch [FILES...]           # Run tests (default: all *.om recursively)
outmatch --fix [FILES...]     # Accept actual output as expected
outmatch -i [FILES...]        # Interactive — review each failure

File Format

Tests live in .om files. Each test starts with a ## header, followed by a $ command and its expected output:

# Comments at column 0

## name of test
  $ command to run
  expected output line
  /regex pattern to match/
  glob: glob pattern to match
  exit 1

Dynamic Test Generation

The | @foreach syntax generates tests from command output — one test per line:

## check each fruit
  $ cat fruits.txt | @foreach @FRUIT
    $ echo "I like @FRUIT"

  apple
    I like apple
  banana
    I like banana

Run outmatch --fix to capture output inline.

How It Differs from Cram

	Cram	Outmatch
Tests per file	One	Many (## headers)
Dynamic generation	No	| @foreach pipelines
Regex matching	re suffix	/pattern/ delimiters
Glob matching	glob suffix	glob: prefix
Fix mode	--interactive	outmatch --fix (automatic)
Generated output	No	Inline, per item
Dependencies	Python 2/3	Python 3.10+, zero deps

License

MIT