Ubuntu Manpage: style - analyse surface characteristics of a document

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 U.S. Navy training manuals; it ranges 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

Flesch Reading Ease formula
Developed by Rudolph Flesch in 1948, the Flesch Reading Ease formula is based on school texts
covering grades 3 to 12. It is widespread, especially in the USA, because it is computed easily
and produces good results. The index ranges from 0 (hard) to 100 (easy). Standard English
documents average around 60 to 70. Applying it to German documents gives poor 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. Texts less than 100 words will not produce 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 was adapted to German by Bamberger and 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.