Commands

Every command accepts --json for machine-readable output. On a TTY without --json, output is rendered with rich tables and highlighted snippets. Claude skills and shell pipelines should always pass --json.

quelle fetch

Resolve a publication by DOI, arXiv id, or free-text title. Walks the source fallback chain (OpenAlex → Crossref enrichment → Semantic Scholar → arXiv → Unpaywall) and returns a normalised JSON Publication.

# DOI — OpenAlex primary, Crossref enrichment.
quelle fetch 10.1109/83.902291
quelle fetch 10.1109/83.902291 --json

# arXiv id — preprint metadata + direct PDF.
quelle fetch 1706.03762

# Free-text title — OpenAlex title search, Crossref fallback.
quelle fetch "The Perceptron: A Probabilistic Model" --json

# Force a network round-trip even if the cache has an entry.
quelle fetch 10.xxxx/yyyy --no-cache

# Download the PDF into the data dir (fallback chain: OpenAlex → arXiv → Unpaywall).
quelle fetch 1706.03762 --download-pdf

Google Scholar URLs are not supported: Scholar has no public API and its ToS prohibits automated access. If you only have a Scholar link, copy the paper title and feed that to quelle fetch — OpenAlex and Crossref together cover almost every paper with a DOI.

Cache commands

The cache is a SQLite database keyed by DOI, arXiv id, OpenAlex id, and normalised title. A second query for the same paper is offline.

quelle cache stats

Per-source counts, hit/miss ratio, total size.

quelle cache stats
quelle cache stats --json

quelle cache list

Enumerate cached entries, newest first.

quelle cache list --limit 20
quelle cache list --json

quelle cache show

Full cached Publication blob for a key.

quelle cache show 10.1109/83.902291
quelle cache show 1706.03762 --json

quelle cache clear

Drop the cache. Prompts unless --yes.

quelle cache clear --yes

Config and init

quelle init

Bootstraps the config, data, and cache dirs and seeds a commented .env. Idempotent — safe to re-run.

quelle init

quelle config

quelle config show                 # all values, API keys redacted
quelle config show --json
quelle config path                 # resolved config / data / cache paths
quelle config path --json
quelle config edit                 # open .env in $EDITOR

quelle --version

quelle --version

Exit codes

quelle maps errors to four exit codes:

Code	Meaning
0	Success
1	User error (bad identifier, unsupported input, missing required env var)
2	Source error (upstream returned an error response, paper not found)
3	Network error (timeout, DNS failure, TLS)
4	Internal error (bug)