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 = 5.89*chars/wds-0.3*sentences/(100*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 bad 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.
-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
specifies the 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 1997–2005 Michael Haardt
<michael@moria.de>.
It contains contributions by Jason Petrone <jpetrone@acm.org> and Uschi
Stegemeier <uschi@morwain.de>.
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 2 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 has been 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 ToolsThe 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.