How to take advantage of Linux's extensive vocabulary

Linux systems don't only know a lot of words, it has commands that can help you use them by finding words that are on the tip of your tongue or fixing your typos.

linux spelling
Sandra Henry-Stocker

While you might not think of Linux as a writing tutor, it does have some commendable language skills – at least when it comes to English. While the average American probably has a vocabulary between 20,000 and 50,000 words, Linux can claim over 100,000 words (spellings, not definitions). And you can easily put this vocabulary to work for you in a number of ways. Let’s look at how Linux can help with your word challenges.

Help with finding words

First, let’s focus on finding words.If you use the wc command to count the number of words in the /usr/share/dict/words file on your system, you should see something like this:

$ wc -l /usr/share/dict/words
102402 /usr/share/dict/words

As you can see, the words file on this system contains 102,402 words. So, when you’re trying to nail down just the right word and are having trouble, you stand a good chance of finding it on your system by remembering (or guessing at) some part of it. But you'll need a little help narrowing down those 102,402 words to a group worth your time to review. In this command, we’re looking for words that start with the letters “revi”.

$ grep ^reviv /usr/share/dict/words
revival
revival's
revivalist
revivalist's
revivalists
revivals
revive
revived
revives
revivification
revivification's
revivified
revivifies
revivify
revivifying
reviving

That’s sixteen words that start with the string “revi”. The ^ character represents the beginning of the word and, as you might have suspected, each word in the file is on a line by itself.

A good number of the words in the /usr/share/dict/words file are names. If you want to  find words regardless of whether they're capitalized, add the -i (ignore case) option to your grep command.

$ grep -i ^wool /usr/share/dict/words
Woolf
Woolf's
Woolite
Woolite's
Woolongong
Woolongong's
Woolworth
Woolworth's
wool
...

You can also look for words that end in or contain a certain string of letters. In this next command, we look for words that contain the string “nativ” at any location.

$ grep 'nativ' /usr/share/dict/words
alternative
alternative's
alternatively
alternatives
imaginative
imaginatively
native
native's
natives
nativities
nativity
nativity's
nominative
nominative's
nominatives
unimaginative

In this next command, we look for words that end in “emblance”, the $ character representing the end of the line. Only two words in the words file fit the bill.

$ grep 'emblance$' /usr/share/dict/words
resemblance
semblance

If we, for some reason, want to find words with exactly 21 letters, we could use this command:

$ grep '^.....................$' /usr/share/dict/words
counterintelligence's
electroencephalograms
electroencephalograph

On the other hand, making sure we've typed the correct number of dots can be tedious. This next command is little easier to manage:

$ grep -E '^[[:alpha:]]{21}$' /usr/share/dict/words
electroencephalograms
electroencephalograph

This command does the same thing:

$ grep -E '^\w{21}$' /usr/share/dict/words
electroencephalograms
electroencephalograph

The one important difference between these commands is that the one with the dots matches any string of 21 characters. The two specifying "alpha" or "\w" only match letters, so they find only two matching words.

Now let’s look for words that contain 20 letters (or more) in a row.

$ grep -E '(\w{20})' /usr/share/dict/words
Andrianampoinimerina
Andrianampoinimerina's
counterrevolutionaries
counterrevolutionary
counterrevolutionary's
electroencephalogram
electroencephalogram's
electroencephalograms
electroencephalograph
electroencephalograph's
electroencephalographs
uncharacteristically

That command returns words with apostrophes because they contain 20 letters in a row before they get to that point.

Next, we’ll check out words with 21 or more characters. The 1 and 20 in combination with the v (invert) option in this command cause grep to skip over words with anywhere from 1 to 20 characters.

$ grep -vwE '\w{1,20}' /usr/share/dict/words
counterrevolutionaries
electroencephalograms
electroencephalograph
electroencephalographs

In this next command, we look for words that start with “ex” and have four additional letters.

$ grep '^ex.\{4\}$' /usr/share/dict/words
exacts
exalts
exam's
exceed
excels
except
excess
excise
excite
excuse
…

In case you're curious, the words file on this system contains 43 such words:

$ grep '^ex.\{4\}$' /usr/share/dict/words | wc -l
43

To get help with spelling, you should try aspell. It can help you with individual words or run a spell check scan through an entire text file. In this first example, we ask aspell to help with a single word. It finds the word we’re after along with a couple other possibilities.

Checking a word

$ aspell -a
@(#) International Ispell Version 3.1.20 (but really Aspell 0.60.7)
prolifferate	<== entered word
& prolifferate 3 0: proliferate, proliferated, proliferates  <== replacement options

If aspell doesn’t provide a list of words, that means that the spelling you offered was correct. Here's an example:

$ aspell -a
@(#) International Ispell Version 3.1.20 (but really Aspell 0.60.7)
proliferate    <== entered text
*              <== no suggestions

Typing ^C (control-c) exits aspell.

Checking a file

When checking a file with aspell, you get suggestions for each misspelled word. When aspell spots typos, it highlights the misspelled words one at a time and gives you a chance to choose from a list of properly spelled words that are similar enough to the misspelled words to be good candidates for replacing them.

To start checking a file, type aspell -c followed by the file name.

$ aspell -c thesis

You'll see something like this:

This thesis focusses on …

1) focuses 6) Fosse's
2) focused 7) flosses
3) cusses  8) courses
4) fusses  9) focus
5) focus's 0) fuses
i) Ignore  I) Ignore all
r) Replace R) Replace all
a) Add     l) Add Lower
b) Abort   x) Exit

Make your selection by pressing the key listed next to the word you want (1, 2, etc.) and aspell will replace the misspelled word in the file and move on to the next one if there are others. Notice that you also have options to replace the word by typing another one. Press "x" when you're done.

Help with crossword puzzles

If you’re working on a crossword puzzle and need to find a five-letter word that starts with a “d” and has a “u” as its fourth letter, you can use a command like this:

$ grep -i '^d..u.$' /usr/share/dict/words
datum
debug
debut
demur
donut

Help with word scrambles

If you’re working on a puzzle that requires you to de-scramble the letters in a string until you've found a proper word, you can offer the list of letters to grep like this example in which grep turns the letters "yxusonlia" into the word “anxiously”.

$ grep -P '^(?:([yxusonlia])(?!.*?\1)){9}$' /usr/share/dict/words
anxiously

Linux’s word skills are impressive and sometimes even fun. Whether you're hoping to find words you can't quite call to mind or get a little help cheating on word puzzles, Linux offers some clever options.

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