Similar Pages
zetl similar "Query" finds pages whose titles are near-matches for the query string. It uses SimHash over page names, which makes it excellent at three things: recovering from typos, spotting duplicate-ish pages you meant to merge, and suggesting links as you type.
zetl similar "Zetelkasten Method"
Zettelkasten Method (distance 3)
Zettelkasten Workflow (distance 7)
Luhmann's Method (distance 11)
The number is Hamming distance on the hash — smaller is more similar. Zero would be identical.
What SimHash does, briefly
SimHash is a locality-sensitive hash: feed it a string, get back a fixed-length binary fingerprint such that similar strings produce similar fingerprints. Unlike a cryptographic hash (where flipping one letter scrambles the whole output), SimHash changes only a few bits when the input changes slightly. Comparing two hashes by Hamming distance — the count of differing bits — gives you a cheap similarity score without storing the originals.
zetl computes one hash per page name at index time. zetl similar then scans them and returns the closest N. No full-text comparison, no embedding model, no network — just arithmetic over bits. It finishes in under a millisecond for vaults of tens of thousands of pages.
The tradeoff: it only sees names. A page titled Dogs and a page titled Canine Companions are not similar to SimHash, even though they are the same topic. For content similarity, use zetl search --semantic (see Searching).
The three flags
| Flag | Default | Use |
|---|---|---|
--threshold N | 12 | Max Hamming distance to report. Lower = stricter |
--limit N | 10 | Max results |
--json | off | Force JSON output |
The default threshold of 12 is tuned to catch typos and near-duplicates without flooding the output. Lower it to 6 if you only want obvious matches; raise it to 20 to see the long tail.
When to use it
Recovering from typos. You vaguely remember a page name, try a spelling, and zetl says “no such page.”
zetl links "Zetelkasten Method"
# error: page not found
zetl similar "Zetelkasten Method"
# Zettelkasten Method (distance 3)
Catching duplicates. Over time you accumulate Deep Work, Deep Work (book), and Deep Work Notes. A periodic zetl similar sweep on your top-linked pages surfaces these before the graph splits in half.
zetl similar "Deep Work" --threshold 8
Suggesting links while writing. Before creating a new page, run zetl similar "Proposed Title". If there is a page at distance 4, you probably meant to link to it, not spawn a sibling.
Example: weekly duplicate audit
A one-liner to find every near-duplicate pair in the vault, suitable for a Sunday cleanup:
zetl list --json \
| jq -r '.pages[].name' \
| while read -r p; do
zetl similar "$p" --threshold 6 --limit 3 --json \
| jq -r --arg p "$p" '.matches[] | select(.name != $p) | "\($p) ~ \(.name) [\(.distance)]"'
done \
| sort -u
Run it once a month; act on the ones you recognise. Most will be false positives (e.g. 2026-04-01 and 2026-04-02 share nearly every bit) — the ones that matter will stand out.