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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 29] 29.10 Just the Words, Please </TITLE><METANAME="DC.title"CONTENT="UNIX Power Tools"><METANAME="DC.creator"CONTENT="Jerry Peek, Tim O'Reilly & Mike Loukides"><METANAME="DC.publisher"CONTENT="O'Reilly & Associates, Inc."><METANAME="DC.date"CONTENT="1998-08-04T21:45:13Z"><METANAME="DC.type"CONTENT="Text.Monograph"><METANAME="DC.format"CONTENT="text/html"SCHEME="MIME"><METANAME="DC.source"CONTENT="1-56592-260-3"SCHEME="ISBN"><METANAME="DC.language"CONTENT="en-US"><METANAME="generator"CONTENT="Jade 1.1/O'Reilly DocBook 3.0 to HTML 4.0"><LINKREV="made"HREF="mailto:online-books@oreilly.com"TITLE="Online Books Comments"><LINKREL="up"HREF="ch29_01.htm"TITLE="29. Spell Checking, Word Counting, and Textual Analysis"><LINKREL="prev"HREF="ch29_09.htm"TITLE="29.9 Looking for Closure "><LINKREL="next"HREF="part05.htm"TITLE="V. Text Editing "></HEAD><BODYBGCOLOR="#FFFFFF"TEXT="#000000"><DIVCLASS="htmlnav"><H1><IMGSRC="gifs/smbanner.gif"ALT="UNIX Power Tools"USEMAP="#srchmap"BORDER="0"></H1><MAPNAME="srchmap"><AREASHAPE="RECT"COORDS="0,0,466,58"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="467,0,514,18"HREF="jobjects/fsearch.htm"ALT="Search this book"></MAP><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch29_09.htm"TITLE="29.9 Looking for Closure "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 29.9 Looking for Closure "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 29<BR>Spell Checking, Word Counting, and Textual Analysis</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="PART"HREF="part05.htm"TITLE="V. Text Editing "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: V. Text Editing "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-7964">29.10 Just the Words, Please </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-32432"></A><ACLASS="indexterm"NAME="AUTOID-32435"></A>In various kinds of textual analysis scripts, you <SPANCLASS="link">sometimes need just the words (<ACLASS="linkend"HREF="ch29_08.htm"TITLE="Find a a Doubled Word ">29.8</A>)</SPAN>.</P><PCLASS="para">I know two ways to do this.The <EMCLASS="emphasis">deroff</EM> command was designed to strip out <SPANCLASS="link"><EMCLASS="emphasis">troff</EM> (<ACLASS="linkend"HREF="ch43_13.htm"TITLE="The Text Formatters nroff, troff, ditroff, ... ">43.13</A>)</SPAN>constructs and punctuation from files.The command <EMCLASS="emphasis">deroff -w</EM>will give you a list of just the words in a document; pipe to <SPANCLASS="link"><EMCLASS="emphasis">sort -u</EM> (<ACLASS="linkend"HREF="ch36_06.htm"TITLE="Miscellaneous sort Hints ">36.6</A>)</SPAN>if you want only one of each.</P><PCLASS="para"><EMCLASS="emphasis">deroff</EM> has one major failing, though.It only considers a wordto be a string of characters beginning with a letter of the alphabet.A single character won't do, which leaves out one-letter words like the indefinite article "A."</P><PCLASS="para">A substitute is <SPANCLASS="link"><EMCLASS="emphasis">tr</EM> (<ACLASS="linkend"HREF="ch35_11.htm"TITLE="Hacking on Characters with tr ">35.11</A>)</SPAN>,which can perform various kinds of character-by-characterconversions.</P><PCLASS="para">To produce a list of all the individual words in a file, type:<ACLASS="indexterm"NAME="AUTOID-32451"></A></P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch13_01.htm"TITLE="13.1 Using Standard Input and Output"><</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen">% <CODECLASS="userinput"><B>tr -cs A-Za-z '\012' <</B></CODE><CODECLASS="replaceable"><I> file</I></CODE></PRE></TD></TR></TABLE></P><PCLASS="para">The <EMCLASS="emphasis">-c</EM> option "complements" the first string passed to<EMCLASS="emphasis">tr</EM>; <EMCLASS="emphasis">-s</EM> squeezes out repeated characters.This has theeffect of saying: "Take any non-alphabetic characters you find (oneor more) and convert them to newlines (\012)."</P><PCLASS="para">(Wouldn't it be nice if <EMCLASS="emphasis">tr</EM> just recognized standard UNIX<SPANCLASS="link">regular expression syntax (<ACLASS="linkend"HREF="ch26_04.htm"TITLE="Using Metacharacters in Regular Expressions ">26.4</A>)</SPAN>?Then, instead of <CODECLASS="literal">-c A-Za-z</CODE>, you'd say <CODECLASS="literal">'[^A-Za-z]'</CODE>.It's not any less obscure, but at least it's used by other programs,so there's one less thing to learn.)</P><PCLASS="para"> The <SPANCLASS="link">System V version of <EMCLASS="emphasis">tr</EM> (<ACLASS="linkend"HREF="ch35_11.htm"TITLE="Hacking on Characters with tr ">35.11</A>)</SPAN>has slightly different syntax. You'd get the same effect with:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>tr -cs '[A-Z][a-z]' '[\012*]' < </B></CODE><CODECLASS="replaceable"><I>file</I></CODE></PRE></BLOCKQUOTE></P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">TOR</SPAN></P></DIV></DIV><DIVCLASS="htmlnav"><P></P><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><TABLEWIDTH="515"BORDER="0"CELLSPACING="0"CELLPADDING="0"><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch29_09.htm"TITLE="29.9 Looking for Closure "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 29.9 Looking for Closure "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="book"HREF="index.htm"TITLE="UNIX Power Tools"><IMGSRC="gifs/txthome.gif"SRC="gifs/txthome.gif"ALT="UNIX Power Tools"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="PART"HREF="part05.htm"TITLE="V. 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