STYLE(1)

NAME
style - analyse surface characteristics of a document

SYNOPSIS
style [-L language] [-l length] [-r ari] [file...]
style [--language language] [--print-long length] [--print-ari ari] [file...]
style -h|--help
style --version

DESCRIPTION
Style analyses the surface characteristics of the writing style of a document. It prints various readability grades, length of words, sentences and paragraphs. It can further locate sentences with certain characteristics. If no files are given, the document is read from standard input.

Numbers are counted as words with one syllable. A sentence is a sequence of words, that starts with a capitalised word and ends with a full stop, double colon, question mark or exclamation mark. A single letter followed by a dot is considered an abbreviation, so it does not end a sentence. Various multi-letter abbreviations are recognized, they do not end a sentence as well. A paragraph consists of two or more new line characters.

  Readability grades
Style understands cpp(1) #line lines for being able to give precise locations when printing sentences.

Kincaid formula
    The Kincaid Formula was developed for Navy training manuals, that ranged in difficulty from 5.5 to 16.3. It is probably best applied to technical documents, because it is based on adult training manuals rather than school book text. Dialogs (often found in fictional texts) are usually a series of short sentences, which lowers the score. On the other hand, scientific texts with many long scientific terms are rated higher, although they are not necessarily harder to read for people who are familiar with those terms.

    Kincaid = 11.8*syllables/wds+0.39*wds/sentences-15.59

Automated Readability Index
    The Automated Readability Index is typically higher than Kincaid and Coleman-Liau, but lower than Flesch.

    ARI = 4.71*chars/wds+0.5*wds/sentences-21.43

Coleman-Liau Formula
    The Coleman-Liau Formula usually gives a lower grade than Kincaid, ARI and Flesch when applied to technical documents.

    Coleman-Liau = 5.88*chars/wds-29.5*sent/wds-15.8

Flesh reading easy formula
    The Flesh reading easy formula was developed by Flesh in 1948 and it is based on school text covering grade 3 to 12. It is wide spread, especially in the USA, because of good results and simple computation. The index is usually between 0 (hard) and 100 (easy), standard English documents averages approximately 60 to 70. Applying it to German documents does not deliver good results because of the different language structure.

    Flesch Index = 206.835-84.6*syll/wds-1.015*wds/sent

Fog Index
    The Fog index was developed by Robert Gunning. Its value is a school grade. The ``ideal'' Fog Index level is 7 or 8. A level above 12 indicates the writing sample is too hard for most people to read. Only use it on texts of at least hundred words to get meaningful results. Note that a correct implementation would not count words of three or more syllables that are proper names, combinations of easy words, or made three syllables by suffixes such as –ed, –es, or –ing.

    Fog Index = 0.4*(wds/sent+100*((wds >= 3 syll)/wds))

Lix formula
    The Lix formula developed by Björnsson from Sweden is very simple and employs a mapping table as well:

    Lix = wds/sent+100*(wds >= 6 char)/wds

    Index | 34 |  | 38 |  | 41 |  | 44 |  | 48 |  | 51 |  | 54 |  | 57
    School year |  | 5 |  | 6 |  | 7 |  | 8 |  | 9 |  | 10 |  | 11

SMOG-Grading
    The SMOG-Grading for English texts was developed by McLaughlin in 1969. Its result is a school grade.

    SMOG-Grading = square root of (((wds >= 3 syll)/sent)*30) + 3

    It has been adapted to German by Bamberger & Vanecek in 1984, who changed the constant +3 to -2.

  Word usage
The word usage counts are intended to help identify excessive use of particular parts of speech.

Verb Phrases
    The category of verbs labeled "to be" identifies phrases using the passive voice. Use the passive voice sparingly, in favor of more direct verb forms. The flag -p causes style to list all occurrences of the passive voice.

The verb category "aux" measures the use of modal auxiliary verbs, such as "can", "could", and "should". Modal auxiliary verbs modify the mood of a verb.

Conjunctions
    The conjunctions counted by style are coordinating and subordinating. Coordinating conjunctions join grammatically equal sentence fragments, such as a noun with a noun, a phrase with a phrase, or a clause to a clause. Coordinating conjunctions are "and," "but," "or," "yet," and "nor."

Subordinating conjunctions connect clauses of unequal status. A subordinating conjunction links a subordinate clause, which is unable to stand alone, to an independent clause. Examples of subordinating conjunctions are "because," "although," and "even if."

Pronouns
    Pronouns are contextual references to nouns and noun phrases. Documents with few pronouns generally lack cohesiveness and fluidity. Too many pronouns may indicate ambiguity.

Nominalizations
    Nominalizations are verbs that are changed to nouns. Style recognizes words that end in "ment," "ance," "ence," or "ion" as nominalizations. Examples are "endowment," "admittance," and "nominalization." Too much nominalization in a document can sound abstract and be difficult to understand. The flag -N causes style to list all nominalizations. The flag -n prints all sentences with either the passive voice or a nominalization.

OPTIONS

-L language, --language language
    set the document language (de, en, nl).

-l length, --print-long length
    print all sentences longer than length words.

-r ari, --print-ari ari
    print all sentences whose readability index (ARI) is greater than ari.

-p passive, --print-passive
    print all sentences phrased in the passive voice.

-N nominalizations, --print-nom
    print all sentences containing nominalizations.

-n nominalizations-passive, --print-nom-passive
    print all sentences phrased in the passive voice or containing nominalizations.

-h, --help
    Print a short usage message.

--version
    Print the version.

ERRORS
On usage errors, 1 is returned. Termination caused by lack of memory is signalled by exit code 2.

ENVIRONMENT

LC_MESSAGES=de|en|nl
    specifies the default document language. The default language is en.

LC_CTYPE=iso-8859-1
    specifies the document character set. The default character set is ASCII.

AUTHOR
This program is GNU software, copyright 1997–2007 Michael Haardt <michael@moria.de>.

It contains contributions by Jason Petrone <jpetrone@acm.org>, Uschi Stegemeier <uschi@morwain.de> and Hans Lodder.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

HISTORY
There was a style command on old UNIX systems, which is now part of the AT&T DWB package. The original version was bound to roff by enforcing a call to deroff.

SEE ALSO
deroff(1), diction(1)

Cherry, L.L.; Vesterman, W.: Writing Tools—The STYLE and DICTION programs, Computer Science Technical Report 91, Bell Laboratories, Murray Hill, N.J. (1981), republished as part of the 4.4BSD User's Supplementary Documents by O'Reilly.

Coleman, M. and Liau,T.L. (1975). 'A computer readability formula designed for machine scoring', Journal of Applied Psychology, 60(2), 283-284.