📄 ch25_12.htm
字号:
<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 25] 25.12 Double Space, Triple 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="1998-08-04T21:43:24Z"><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_11.htm"TITLE="25.11 crush: A cat that Skips all Blank Lines "><LINKREL="next"HREF="ch25_13.htm"TITLE="25.13 pushin: Squeeze Out Extra White Space "></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_11.htm"TITLE="25.11 crush: A cat that Skips all Blank Lines "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.11 crush: A cat that Skips all Blank Lines "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_13.htm"TITLE="25.13 pushin: Squeeze Out Extra White Space "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 25.13 pushin: Squeeze Out Extra White Space "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-4290">25.12 Double Space, Triple Space ... </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-27860"></A><ACLASS="indexterm"NAME="AUTOID-27863"></A><ACLASS="indexterm"NAME="AUTOID-27866"></A><ACLASS="indexterm"NAME="AUTOID-27868"></A><ACLASS="indexterm"NAME="AUTOID-27872"></A>Here are handy scripts for printing drafts of files.They double-space or triple-space file(s) or standard input.For example:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>doublespace afile | lp</B></CODE>% <CODECLASS="userinput"><B>prog | triplespace | lp</B></CODE></PRE></BLOCKQUOTE></P><TABLECLASS="para.programreference"BORDER="1"><TR><THVALIGN="TOP"><ACLASS="programreference"HREF="examples/index.htm"TITLE="doublespace">doublespace</A><BR><ACLASS="programreference"HREF="examples/index.htm"TITLE="triplespace">triplespace</A><BR></TH><TDVALIGN="TOP">Here they are: </TD></TR></TABLE><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen"><EMCLASS="emphasis">doublespace</EM> <EMCLASS="emphasis">triplespace</EM>#!/bin/sed -f #!/bin/sed -fG G G</PRE></BLOCKQUOTE></P><PCLASS="para">No, that isn't a typo: both scripts just use the <EMCLASS="emphasis">sed</EM> command<SPANCLASS="link"><EMCLASS="emphasis">G</EM> (<ACLASS="linkend"HREF="ch34_24.htm"TITLE="Quick Reference: sed ">34.24</A>)</SPAN>.The <EMCLASS="emphasis">G</EM> command appends a newline and the contents of <EMCLASS="emphasis">sed</EM>'s holdspace, which will be empty in this script.The effect is to add a newline after every newline; two <EMCLASS="emphasis">G</EM>s add twonewlines.</P><PCLASS="para">That file doesn't even use a shell, so it's efficient; the kernel<SPANCLASS="link">starts <EMCLASS="emphasis">sed</EM> directly (<ACLASS="linkend"HREF="ch45_03.htm"TITLE="Don't Need a Shell for Your Script? Don't Use One ">45.3</A>)</SPAN>and gives it the script itself as the input file expected with the<EMCLASS="emphasis">-f</EM> option.If your UNIX can't execute files directly with <CODECLASS="literal">#!</CODE>, typein these versionsinstead:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen"> <EMCLASS="emphasis">doublespace</EM> <EMCLASS="emphasis">triplespace</EM>exec /bin/sed G ${1+"$@"} exec /bin/sed 'G;G' ${1+"$@"}</PRE></BLOCKQUOTE></P><PCLASS="para"> They start a shell, then<SPANCLASS="link"><EMCLASS="emphasis">exec</EM> replaces the shell with <EMCLASS="emphasis">sed</EM> (<ACLASS="linkend"HREF="ch45_07.htm"TITLE="The exec Command ">45.7</A>)</SPAN>.The <CODECLASS="literal">${1+"$@"}</CODE> works around a<SPANCLASS="link">problem with argument handling (<ACLASS="linkend"HREF="ch46_07.htm"TITLE="Quoting and Command-Line Parameters ">46.7</A>)</SPAN>in some Bourne shells.</P><PCLASS="para">And now you know how to make <EMCLASS="emphasis">quadruplespace</EM>,<EMCLASS="emphasis">quintuplespace</EM>, ... <CODECLASS="literal">:-)</CODE>.</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_11.htm"TITLE="25.11 crush: A cat that Skips all Blank Lines "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.11 crush: A cat that Skips all Blank Lines "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_13.htm"TITLE="25.13 pushin: Squeeze Out Extra White Space "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 25.13 pushin: Squeeze Out Extra White Space "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">25.11 crush: A cat that Skips all Blank Lines </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">25.13 pushin: Squeeze Out Extra White Space </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
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -