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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 25] 25.6 What's in That White Space? </TITLE><METANAME="DC.title"CONTENT="UNIX Power Tools"><METANAME="DC.creator"CONTENT="Jerry Peek, Tim O'Reilly &amp; Mike Loukides"><METANAME="DC.publisher"CONTENT="O'Reilly &amp; Associates, Inc."><METANAME="DC.date"CONTENT="1998-08-04T21:43:11Z"><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="ch25_01.htm"TITLE="25. Showing What's in a File"><LINKREL="prev"HREF="ch25_05.htm"TITLE="25.5 Page Through Compressed, RCS, Unprintable Files "><LINKREL="next"HREF="ch25_07.htm"TITLE="25.7 Show Non-Printing Characters with cat -v or od -c "></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="ch25_05.htm"TITLE="25.5 Page Through Compressed, RCS, Unprintable Files "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.5 Page Through Compressed, RCS, Unprintable Files "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 25<BR>Showing What's in a File</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch25_07.htm"TITLE="25.7 Show Non-Printing Characters with cat -v or od -c "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 25.7 Show Non-Printing Characters with cat -v or od -c "BORDER="0"></A></TD></TR></TABLE>&nbsp;<HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-2641">25.6 What's in That White Space? </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="UPT-ART-2641-IX-SPECIAL-CHARACTERS-CAT-COMMAND-FOR-VIEWING"></A><ACLASS="indexterm"NAME="AUTOID-27461"></A><ACLASS="indexterm"NAME="AUTOID-27464"></A><ACLASS="indexterm"NAME="AUTOID-27467"></A><ACLASS="indexterm"NAME="AUTOID-27470"></A>The <EMCLASS="emphasis">cat</EM><SPANCLASS="link"><EMCLASS="emphasis">-v</EM> option (<ACLASS="linkend"HREF="ch25_07.htm"TITLE="Show Non-Printing Characters with cat -v or od -c ">25.7</A>)</SPAN>shows non-printable characters in a printable way.<EMCLASS="emphasis">cat</EM> has two options for displaying white space in a line.If you use the <EMCLASS="emphasis">-t</EM> option with <EMCLASS="emphasis">-v</EM>, TABcharacters are shown as<CODECLASS="literal">^I</CODE>.The <EMCLASS="emphasis">-e</EM> option combined with <EMCLASS="emphasis">-v</EM> marks the end of each linewith a <CODECLASS="literal">$</CODE> character.Some versions of <EMCLASS="emphasis">cat</EM> don't require the <EMCLASS="emphasis">-v</EM> with those options.Let's compare a one-line file without and with the <EMCLASS="emphasis">-t -e</EM> (whichhave to be typed separately, by the way; <EMCLASS="emphasis">-te</EM> won't work):</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>cat afile</B></CODE>This is a one-line file - boring, eh?% <CODECLASS="userinput"><B>cat -v -t -e afile</B></CODE>ThiS^Hs is^Ia one-line file^I- boring, eh?       $</PRE></BLOCKQUOTE></P><PCLASS="para">Although you can't tell it from plain <EMCLASS="emphasis">cat</EM>, there's a backspace(CTRL-h) before the first <CODECLASS="literal">s</CODE>, two TABs that take up onlyone column of white space each, and seven spaces at the end of the line.Knowing this can help you debug problems in printing and displaying files.It's also a help for shell programmers who need to parse or sort the outputof other programs.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">JP</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="ch25_05.htm"TITLE="25.5 Page Through Compressed, RCS, Unprintable Files "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.5 Page Through Compressed, RCS, Unprintable Files "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="SECT1"HREF="ch25_07.htm"TITLE="25.7 Show Non-Printing Characters with cat -v or od -c "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 25.7 Show Non-Printing Characters with cat -v or od -c "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">25.5 Page Through Compressed, RCS, Unprintable Files </TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><ACLASS="index"HREF="index/idx_0.htm"TITLE="Book Index"><IMGSRC="gifs/index.gif"SRC="gifs/index.gif"ALT="Book Index"BORDER="0"></A></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172">25.7 Show Non-Printing Characters with cat -v or od -c </TD></TR></TABLE><HRALIGN="LEFT"WIDTH="515"TITLE="footer"><IMGSRC="gifs/smnavbar.gif"SRC="gifs/smnavbar.gif"USEMAP="#map"BORDER="0"ALT="The UNIX CD Bookshelf Navigation"><MAPNAME="map"><AREASHAPE="RECT"COORDS="0,0,73,21"HREF="../index.htm"ALT="The UNIX CD Bookshelf"><AREASHAPE="RECT"COORDS="74,0,163,21"HREF="index.htm"ALT="UNIX Power Tools"><AREASHAPE="RECT"COORDS="164,0,257,21"HREF="../unixnut/index.htm"ALT="UNIX in a Nutshell"><AREASHAPE="RECT"COORDS="258,0,321,21"HREF="../vi/index.htm"ALT="Learning the vi Editor"><AREASHAPE="RECT"COORDS="322,0,378,21"HREF="../sedawk/index.htm"ALT="sed &amp; awk"><AREASHAPE="RECT"COORDS="379,0,438,21"HREF="../ksh/index.htm"ALT="Learning the Korn Shell"><AREASHAPE="RECT"COORDS="439,0,514,21"HREF="../lrnunix/index.htm"ALT="Learning the UNIX Operating System"></MAP></DIV></BODY></HTML>
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