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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 25] 25.9 Adding and Deleting White Space </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="1998-08-04T21:43:18Z"><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_08.htm"TITLE="25.8 Finding File Types "><LINKREL="next"HREF="ch25_10.htm"TITLE="25.10 Squash Extra Blank Lines "></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_08.htm"TITLE="25.8 Finding File Types "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.8 Finding File Types "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_10.htm"TITLE="25.10 Squash Extra Blank Lines "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 25.10 Squash Extra Blank Lines "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-7430">25.9 Adding and Deleting White Space </A></H2><PCLASS="para">There are a lot of ways to change the amount of white space (space and tabcharacters) in a line:<ACLASS="indexterm"NAME="UPT-ART-7430-IX-WHITESPACE-ADDING-OR-DELETING"></A><ACLASS="indexterm"NAME="UPT-ART-7430-IX-DELETING-WHITESPACE"></A><ACLASS="indexterm"NAME="UPT-ART-7430-IX-FILES-DISPLAYING-CONTENTS-WHITESPACE"></A></P><ULCLASS="itemizedlist"><LICLASS="listitem"><PCLASS="para">Berkeley systems have<SPANCLASS="link"><EMCLASS="emphasis">cat -s</EM> (<ACLASS="linkend"HREF="ch25_10.htm"TITLE="Squash Extra Blank Lines ">25.10</A>)</SPAN>to replace sets of two or more blank lines with single blank lines.If you don't have <EMCLASS="emphasis">cat -s</EM> or need something different, look atarticle<ACLASS="xref"HREF="ch34_18.htm"TITLE="Multiline Delete ">34.18</A>.</P></LI><LICLASS="listitem"><PCLASS="para">The<SPANCLASS="link"><EMCLASS="emphasis">crush</EM> (<ACLASS="linkend"HREF="ch25_11.htm"TITLE="crush: A cat that Skips all Blank Lines ">25.11</A>)</SPAN>script removes all blank lines.</P></LI><LICLASS="listitem"><PCLASS="para">Use<SPANCLASS="link"><EMCLASS="emphasis">doublespace</EM> and <EMCLASS="emphasis">triplespace</EM> (<ACLASS="linkend"HREF="ch25_12.htm"TITLE="Double Space, Triple Space ... ">25.12</A>)</SPAN>to double- and triple-space text.</P></LI><LICLASS="listitem"><PCLASS="para">The<SPANCLASS="link"><EMCLASS="emphasis">pushin</EM> (<ACLASS="linkend"HREF="ch25_13.htm"TITLE="pushin: Squeeze Out Extra White Space ">25.13</A>)</SPAN>script replaces multiple white space characters with a single space.This can shorten long lines.</P></LI><LICLASS="listitem"><PCLASS="para">You can use <EMCLASS="emphasis">sed</EM> to<SPANCLASS="link">indent lines of text before printing (<ACLASS="linkend"HREF="ch43_09.htm"TITLE="Indenting Text for Printing ">43.9</A>)</SPAN>.The<SPANCLASS="link"><EMCLASS="emphasis">offset</EM> (<ACLASS="linkend"HREF="ch35_07.htm"TITLE="offset: Indent Text ">35.7</A>)</SPAN>shell scriptdoes that more easily.</P></LI><LICLASS="listitem"><PCLASS="para">For other jobs, utilities like<SPANCLASS="link"><EMCLASS="emphasis">awk</EM> (<ACLASS="linkend"HREF="ch33_11.htm"TITLE="Quick Reference: awk ">33.11</A>)</SPAN>and<SPANCLASS="link"><EMCLASS="emphasis">sed</EM> (<ACLASS="linkend"HREF="ch34_24.htm"TITLE="Quick Reference: sed ">34.24</A>)</SPAN>will probably do what you want.You have to understand how to program them before you use them.</P></LI></UL><ACLASS="indexterm"NAME="AUTOID-27774"></A><ACLASS="indexterm"NAME="AUTOID-27775"></A><ACLASS="indexterm"NAME="AUTOID-27776"></A><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_08.htm"TITLE="25.8 Finding File Types "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.8 Finding File Types "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_10.htm"TITLE="25.10 Squash Extra Blank Lines "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 25.10 Squash Extra Blank Lines "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">25.8 Finding File Types </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">25.10 Squash Extra Blank Lines </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 & 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>⌨️ 快捷键说明
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