CLI Usage

Complete command-line reference for Snapshot Comparison.

Synopsis

snapcmp <COMMAND> [OPTIONS]

Commands

create

Create a new snapshot from stdin.

snapcmp create <name> [OPTIONS]

Arguments:

• <name> - Snapshot name (no path separators)

Example:

echo "Hello" | snapcmp create greeting
# Output: Created snapshot 'greeting' (6 bytes, type: Text)

cat data.json | snapcmp create config -t json
# Output: Created snapshot 'config' (128 bytes, type: Json)

check

Check stdin against a stored snapshot.

snapcmp check <name> [OPTIONS]

Arguments:

• <name> - Snapshot name to check against

Behavior:

• Returns exit code 0 on match
• Returns exit code 1 on mismatch (prints diff)
• With --update, updates snapshot instead of failing

Example:

echo "Hello" | snapcmp check greeting
# Output: ✓ Snapshot 'greeting' matches

echo "Changed" | snapcmp check greeting
# Output: ✗ Snapshot 'greeting' does not match
# [Diff output]
# Exit code: 1

echo "Changed" | snapcmp check greeting --update
# Output: ↻ Snapshot 'greeting' updated
# Exit code: 0

update

Update an existing snapshot with new content.

snapcmp update <name> [OPTIONS]

Arguments:

• <name> - Snapshot name to update

Example:

echo "New content" | snapcmp update greeting
# Output: Updated snapshot 'greeting' (12 bytes)

list

List all snapshots in the store.

snapcmp list [OPTIONS]

Example:

snapcmp list
# Output:
# Snapshots in 'snapshots':
#
#   greeting (6 bytes, Text)
#   config (128 bytes, Json)
#
# Total: 2 snapshot(s)

delete

Delete a snapshot.

snapcmp delete <name> [OPTIONS]

Arguments:

• <name> - Snapshot name to delete

Example:

snapcmp delete old-test
# Output: Deleted snapshot 'old-test'

clean

Remove orphaned snapshots not in a keep list.

snapcmp clean --keep <names> [OPTIONS]

Arguments:

• --keep <names> - Comma-separated list of snapshot names to keep

Example:

# See what would be deleted
snapcmp clean --keep test-1,test-2 --dry-run
# Output: Would delete 3 snapshot(s):
#   old-test-1
#   old-test-2
#   deprecated

# Actually delete
snapcmp clean --keep test-1,test-2
# Output: Deleted 3 snapshot(s):
#   old-test-1
#   old-test-2
#   deprecated

Options

-d, --dir <PATH>

Snapshot directory (default: ./snapshots)

snapcmp list -d my-snapshots
echo "test" | snapcmp create test -d /tmp/snapshots

-t, --type <TYPE>

File type hint (default: auto-detect)

Values: text, json, binary

cat data.json | snapcmp create config -t json
cat image.png | snapcmp create logo -t binary

-c, --color

Enable colored diff output.

echo "changed" | snapcmp check test --color

-u, --update

Update mode: update snapshot on mismatch instead of failing.

echo "new content" | snapcmp check test --update

--context <N>

Number of context lines in diff output (default: 3).

echo "changed" | snapcmp check test --context 5

--keep <names>

Comma-separated list of snapshot names to keep (for clean command).

snapcmp clean --keep test-1,test-2,important

--dry-run

For clean: show what would be deleted without deleting.

snapcmp clean --keep active-tests --dry-run

-h, --help

Show help message.

snapcmp --help
snapcmp create --help

-V, --version

Show version information.

snapcmp --version

Exit Codes

Code	Meaning
0	Success (match, update, or operation completed)
1	Error (mismatch, not found, invalid input)

Examples

CI Integration

#!/bin/bash
set -e

# Check all API snapshots
for endpoint in users products orders; do
    curl -s "https://api.example.com/$endpoint" | snapcmp check "api-$endpoint"
done

echo "All API responses match snapshots"

Development Workflow

# Run tests, update snapshots if needed
./run-tests.sh | snapcmp check test-output --update

# Review changes
git diff snapshots/

Binary Snapshots

# Create binary snapshot
./generate-image.sh | snapcmp create logo -t binary

# Check binary output
./generate-image.sh | snapcmp check logo -t binary