Lexitron

A command-line regex search engine for the English language.

Requirements

The only requirement is Python 3.9 or later.

If you try to install Lexitron and something goes wrong, let me know what your system details are and I'll try to get it fixed.

Installation

Lexitron is available on the Python Package Index (pip). To install, simply type

$ pip install lexitron

at the command line.

Once the install is complete, you can access Lexitron with the lx command at the terminal.

Quick tour

• lx '.*icide': words ending in "icide"
• lx -s rdb: words containing "rdb" anywhere
• lx 'b.a.k': five-letter words matching B?A?K
• lx -a listen: anagrams of "listen"
• lx -f aeilnrst: words you can spell from these letters
• lx -f abcdef.: the same, with a blank tile
• lx -l 4- -rf eihnglw -s h: today's Spelling Bee (center letter "h")
• lx -i q -e u: words with a "q" but no "u"
• lx -t a.a.a: words shaped like "rarer"
• lx -w crane:..y.g: Wordle candidates
• lx --hooks cat: Scrabble hooks for "cat"
• lx -n '.*tion': how many words end in "tion"

More in Examples.

Usage

Usage syntax is

$ lx [options] [expression]
$ lx -f|-a [options] letters [expression]

where expression is a regular expression and [options] are as follows. The expression can be left out when another option says what to look for (lx -t abba, lx -w crane:..y.g).

The expression must match the whole word, so lx cat finds only "cat", and lx ".*cat" finds words ending in "cat". To match the expression anywhere within a word, use -s (so lx -s cat finds "cat", "catalog", "bobcat", etc).

Inflected forms (plurals, conjugations, etc, like "went" or "oxen") are searched along with base forms. Use -b to search base forms only. Phrases with spaces are listed in their base form only ("sperm whale", not "sperm whales").

Searches are case-insensitive unless you use -c. Options can go before or after the expression. Quote the expression ('...') so your shell doesn't interpret characters like *, ? and $.

zsh tip: add alias lx='noglob lx' to your ~/.zshrc and you can skip the quotes for * and ?: lx .*icide, lx colou?r.

A little regex

Expressions, letters and patterns

The same characters mean different things in different places:

• In the expression, they're regex: lx 'dot?' finds "do" and "dot" (? makes the "t" optional).
• In letters (-f, -a), each letter is a tile and . is a blank: lx -a dot. finds "dote", "doth", "toad" and so on.
• In a pattern (-t), each letter is a placeholder: lx -t abba finds "deed", "noon" and so on.

How the expression matches

Spelling from letters

With -f and -a, the letters come first, optionally followed by an expression: lx -a aerst finds all anagrams of "aerst", lx -a aerst 's.*' only the ones starting with "s". Lengths and letters count letters only, ignoring apostrophes, hyphens and spaces.

In the letters, . is a blank tile that can stand for any one letter: lx -f abcdef.. With -a, blanks must be used, like the rest of the letters.

More filters

In a pattern, each letter stands for some letter: the same letter for the same letter, different letters for different ones. . is any letter. So abba matches "deed" but not "dddd", and a.a.a matches "rarer". The pattern only describes shape; to fix actual letters, add an expression: lx -t a.a.a 'r.*'.

Word games

-w sets the length from the guess, and uses level 50 unless you give -L, since Wordle answers are everyday words. A repeated letter is handled the way Wordle does it: in geese:.y..., the grey second and third "e" mean the word has exactly one "e".

With -w, the best guesses come first (-o best), each with its score: how evenly its colors would split the remaining candidates, as expected information in bits. A higher score means fewer candidates left, on average.

Sometimes a word that can't be the answer would narrow things down more, for example by trying five new letters rather than repeating a green one. In a terminal, up to 10 of these come first when they beat every candidate, dimmed (or marked * when NO_COLOR is set). On a tie the candidate wins, since it might be right. Piped output lists only the candidates. Use --probes to see only these words: the 20 best and, after a ... row, the 20 worst.

--plus, --minus and --change take an optional count, cat:2 for two letters. These and --hooks skip words with apostrophes. In a terminal, --hooks shows the front hooks, the word and the back hooks; with -x or when piped, it lists the hooked words.

Which words to search

Output

Type $ lx -h for full help text.

If you aren't familiar with regular expressions, it isn't too hard to learn the basics. There are many resources online. A good starting point is the Wikipedia article.

Output

By default, Lexitron will output a well-formatted (potentially multi-column) list of words. Use -I to add a header describing the results.

Words are sorted alphabetically, except that inflected forms (plurals, conjugations and so on) come right after their base form when it's also in the results: "run ran running runs runabout". In a terminal, the inflected forms are dimmed, so each family stands out, and the other words are colored by how common they are: bold green for core vocabulary, then green, yellow and orange, to red for the most obscure (see Word list). -o alpha sorts strictly alphabetically, with the same styling. Set NO_COLOR in your environment to turn styling off.

The results are separated into "proper" words (containing capitals, like "France" or "USA") and "common" words (lowercase, like "boat").

Using the -x flag will return a more machine-readable output with one word per line. This is also what you get automatically when the output isn't a terminal (e.g. when piping into another command or redirecting to a file). In that case the -I header goes to stderr, so it doesn't get mixed in with the words.

Word list

Lexitron's dictionary comes from the English Speller Database (SCOWL), which grades every word by how well known it is:

All spellings are included: American, British, Canadian and Australian ("color" and "colour", "organize" and "organise"). Accents are removed ("café" becomes "cafe"). Possessives, abbreviations and Roman numerals are left out.

Examples

Word games

NYT Spelling Bee. Words of 4 or more letters, using only the seven letters (each as often as you like), that contain the center letter "h" (-s h). Spelling Bee doesn't accept contractions like "he'll".

$ lx -I -l 4- -rf eihnglw -s h
38 matches for /h/ from 'eihnglw' length 4-

ghee         high         wheelie
ghillie      hill         wheen
he'll        hinge        when
heel         hinging      whew
heeling      neigh        while
heinie       neighing     whiling
hell         nigh         whin
henge        nihil        whine
hewing       weigh        whining
hewn         weighing     whinge
hieing       whee         whingeing
higgle       wheel        whinging
higgling     wheeling

Spelling Bee pangrams. -ra finds words that use every one of the letters, each as often as you like.

$ lx -ra eihnglw
wheeling

Wordle. One -w per guess: g for green, y for yellow, . for grey. The best next guesses come first, with how much each would tell you, in bits. The starred words can't be the answer, but would narrow things down more than any word that could.

$ lx -w crane:.g...
pouts 4.88*    trims 4.19     drugs 3.74     frisk 3.36     brood 3.06
plots 4.82*    profs 4.14     troop 3.73     trout 3.33     groom 3.04
typos 4.78*    prism 4.14     proud 3.72     prior 3.30     brusk 3.00
posit 4.76*    frost 4.13     drift 3.69     proof 3.29     wroth 2.90
moist 4.70*    proms 4.10     group 3.67     brisk 3.28     privy 2.87
omits 4.70*    dript 4.09     trust 3.64     promo 3.21     troth 2.86
plods 4.68*    prows 4.08     trump 3.64     growl 3.19     drill 2.86
pilot 4.67*    gript 4.08     drums 3.62     drily 3.18     broom 2.86
tipsy 4.62*    writs 3.97     fruit 3.61     drool 3.17     grill 2.84
foist 4.60*    prosy 3.96     orbit 3.56     frump 3.17     droll 2.83
trips 4.48     grids 3.95     grubs 3.54     brush 3.17     proxy 2.82
trios 4.41     wrist 3.95     brows 3.53     troll 3.15     druid 2.79
prods 4.33     tromp 3.87     drubs 3.53     grimy 3.15     frill 2.67
prigs 4.30     brigs 3.86     droop 3.51     froth 3.14     truth 2.60
drops 4.30     frogs 3.82     truss 3.51     truly 3.13     brook 2.43
drips 4.27     trots 3.79     dross 3.48     trill 3.12     gruff 2.43
grits 4.25     props 3.75     prowl 3.44     broil 3.11     dryly 2.17
grist 4.22     grows 3.74     gross 3.43     broth 3.07     frizz 1.91
grips 4.20     brims 3.74     tryst 3.40     primp 3.07     wryly 1.78

After a second guess, the best you can do is a guess that might be right:

$ lx -w crane:..y.g -w toils:.y...
abode 2.00
above 2.00
adobe 2.00
awoke 0.81

Wordle, by hand. The same kind of search as a regex: "r" is second and "n" is fourth, there's an "e" somewhere, and "o", "s" and "t" are out. (?=.*e) is a lookahead: "contains an e".

$ lx '(?=.*e)[^ost]r[^ost]n[^ost]'
arena
brine
crane
crine
frena
prune
urine

Scrabble hooks. Letters that make a word when put in front of "at", and after it.

$ lx --hooks at
bcefghklmoprstvw  at  e

Q without U.

$ lx -i q -e u
faqir        qindarka
faqirs       qindarkas
niqab        qintar
qadi         qintars
qadis        qoph
qi           qophs
qibla        qwerty
qiblas       sheqalim
qiblah       sheqel

Word ladders. Every word one letter away from "love".

$ lx --change love
cove
dove
hove
lave
live
lobe
lode
loge
lone
lope
lore
lose
move
rove
wove

Adding a letter.

$ lx --plus cat
cant
cart
cast
cate
cats
chat
coat
scat

Crossword fill. Five letters, B?A?K, most common first.

$ lx -o common 'b.a.k'
black
blank

Scrabble bingos. Every anagram of a rack.

$ lx -a retains
antsier
nastier
retains
retinas
retsina
stainer
stearin

Words from a rack. Five-letter words from "aeilnrst", most common first.

$ lx -o common -l 5 -f aeilnrst | head
aisle
alert
alien
aline
alter
aren't
arise
earls
earns
inert

Blank tiles. . stands for any one letter. Six-letter words or longer from "abcdef" plus a blank:

$ lx -l 6- -f abcdef.
abduce
bached
backed
barfed
braced
cabbed
cabled
chafed
decaff
decafs
deface
fabled
facade

and the anagrams that use every tile:

$ lx -a zebr.
braze
zebra

Exploring English

Words ending in "icide".

$ lx ".*icide"
aborticide      herbicide       patricide
acaricide       homicide        pesticide
algicide        infanticide     regicide
bactericide     insecticide     rodenticide
deicide         larvicide       sororicide
feticide        liberticide     spermicide
filicide        matricide       suicide
foeticide       menticide       tyrannicide
fratricide      miticide        uxoricide
fungicide       parasiticide    vaticide
germicide       parricide       vermicide

Words containing "rdb", with the info header.

$ lx -Is rdb
18 matches for /rdb/

birdbath       hardbitten
birdbaths      hardboard
birdbrain      hardbound
birdbrains     swordbill
birdbrained    swordbills
cardboard      wordbook
hardback       wordbooks
hardbacks      yardbird
hardball       yardbirds

Words shaped like "rarer": the same letter first, third and last.

$ lx -t a.a.a
abaca
abaya
afara
agama
asana
duded
ninon
ovolo
popup
rarer
sises

Seven-letter palindromes with four different letters, mirrored.

$ lx -t abcdcba
deified
racecar
reviver
rotator

No vowels, six letters or more.

$ lx -e aeiou -l 6-
crwths     rhythms
crypts     spryly
flybys     sylphs
ghylls     synchs
glyphs     synths
nymphs     syzygy
psychs     trysts
rhythm     tsktsk

All five vowels, in order.

$ lx '[^aeiou]*a[^aeiou]*e[^aeiou]*i[^aeiou]*o[^aeiou]*u[^aeiou]*'
abstemious
abstemiously
arsenious
facetious
facetiously

The longest words you can type on the top row of a keyboard.

$ lx -o length '[qwertyuiop]+' | tail -3
proprietor
repertoire
typewriter

How many words end in "tion"?

$ lx -n ".*tion"
2299

(Take this with a grain of salt: it depends on what you count as a word, and which technical or niche jargons are included. Try -L 95 to include obscure words.)

Words ending in "woman" versus words ending in "man" but not "woman". (?<!wo) is a lookbehind: "not preceded by wo".

$ lx -n ".*woman"
72

$ lx -n '.*(?<!wo)man'
323

The same double letter twice, except vowels and "s" (to skip "-lessness"), including proper words. \1 repeats whatever (...) matched, and -b leaves out plurals like "hillbillies".

$ lx -Ibus "([^aeious])\1.*\1\1"
50 matches for /([^aeious])\1.*\1\1/ (8 proper, 42 common)

Allhallowmas
Allhallows
Allhallowtide
Boccaccio
Chancellorsville
Connellsville
Llewellyn
Ulladulla

acciaccatura        hullaballoo         pralltriller
allegorically       idyllically         razzamatazz
allergically        illegally           razzmatazz
ballistically       illiberally         riffraff
bellpull            illogically         rollerball
chiffchaff          intellectually      scuttlebutt
collaterally        jellyroll           skillfully
colloquially        kinnikinnick        syllabically
dillydally          metallically        syllogistically
dullsville          millennially        unskillfully
elliptically        monosyllabically    villanelle
flibbertigibbet     pellmell            volleyball
granddaddy          phallically         whippersnapper
hillbilly           pizzazz             willfully

Acronyms of five or more letters: proper words only (-U), in capitals (-c).

$ lx -Uc '[A-Z]{5,}' | head
ALGOL
ANZUS
ASCII
ASEAN
ASPCA
AWACS
BAFTA
BASIC
BOGOF
CAPTCHA

Phrases and compounds ending in "cake".

$ lx -p ".*cake" | head
angel cake
angel food cake
beefcake
buckwheat cake
cake
cheesecake
coffee cake
coffeecake
cotton cake
cupcake

Only phrases. -P leaves out single words.

$ lx -P 'sperm.*'
sperm bank
sperm cell
sperm oil
sperm whale
spermatic cord

Using Lexitron from Python

>>> from lexitron import search
>>> search('.*icide', sort='common')['common'][:3]
['fungicide', 'germicide', 'homicide']

search() takes the same options as the command line; see its docstring.

Changes in version 4.0

• New filters: -i (must contain these letters), -e (must not contain them) and -t (pattern: abba matches "deed", a.a.a matches "rarer").
• New word-game options: -w for Wordle (sorted best guess first), --plus, --minus and --change for adding, removing and changing letters, and --hooks for Scrabble hooks.
• New sort order -o best: best Wordle guess first. In a terminal, -w shows the bits of information each guess would give, with better guesses that can't be the answer first; --probes lists only those.
• -i now means --include. The info header is -I.
• Blank tiles in -f and -a letters are . only, matching . in expressions and patterns; ? is no longer accepted.
• The expression can be left out when another option says what to search for.
• Shorter help, with options in a more sensible order, and a note on what . means in expressions, letters and patterns.
• The old option names --only-phrases and --only-uppercase are gone.

Changes in version 3.3.1

• Long option names are consistent: --only-phrases and --only-uppercase are now --phrases-only and --uppercase-only, like --base-only and --number-only. The old names still work.

Changes in version 3.3

• Phrases with spaces are listed in their base form only: "sperm whale" but not "sperm whales". SCOWL lists inflected forms for only a few phrases, so they're left out for consistency. Hyphenated words keep theirs ("x-rayed").

Changes in version 3.2

• New option -P searches only phrases and hyphenated entries, like "sperm whale"; -p still adds them to the usual results.

Changes in version 3.1

• New default sort, family: alphabetical, with inflected forms right after their base form ("run ran running runs"). -o alpha gives the old order.
• Terminal output is styled: inflected forms listed under their base form are dimmed, and other words are colored by how common they are, from bold green to red. Set NO_COLOR to turn this off; piped output is never styled.

Changes in version 3.0

• New word list: SCOWL replaces AGID, adding everyday words AGID was missing ("a", "of", "from"), British and other spellings, and obscurity levels (-L). The default level leaves out very obscure words; use -L 95 to search everything.
• Expressions now match the whole word by default. In 2.x, lx cat matched any word containing "cat"; to get that behavior now, use lx -s cat.
• Inflected forms (plurals, conjugations, etc) are now searched too; use -b to search base forms only, as in 2.x.
• New options: letters (-f, -a, -r, with blank tiles), length (-l), sorting (-o), phrases (-p) and case-sensitive search (-c).
• Options can go anywhere on the command line.
• Output no longer crashes when piped or redirected; it falls back to one word per line.
• -i with -n prints the header line; -u and -U can no longer be combined.
• Invalid regular expressions give a short error message instead of a traceback.
• Quotation marks in the expression are no longer stripped, so you can search for words containing apostrophes.
• Lexitron can be used as a Python library.
• Requires Python 3.9 or later.

Acknowledgements

For its dictionary, Lexitron uses the English Speller Database (ESDB, previously known as SCOWL) by Kevin Atkinson. See wordlist.aspell.net and lexitron/SCOWL-Copyright.txt for its copyright and license.

Versions before 3.0 used the Automatically Generated Inflection Database (AGID), also by Kevin Atkinson.

License

Lexitron is licensed under GNU GPL Version 2.

Contact

Questions, bug reports, and feature requests can be filed on the Github issues tracker.