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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 9] 9.15 Throwaway Scripts for Complicated Commands </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="1998-08-04T21:35:11Z"><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="ch09_01.htm"TITLE="9. Saving Time on the Command Line"><LINKREL="prev"HREF="ch09_14.htm"TITLE="9.14 Using Here Documents for Form Letters, etc. "><LINKREL="next"HREF="ch09_16.htm"TITLE="9.16 Command Substitution "></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="ch09_14.htm"TITLE="9.14 Using Here Documents for Form Letters, etc. "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 9.14 Using Here Documents for Form Letters, etc. "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 9<BR>Saving Time on the Command Line</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch09_16.htm"TITLE="9.16 Command Substitution "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 9.16 Command Substitution "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-7330">9.15 Throwaway Scripts for Complicated Commands </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-10574"></A><ACLASS="indexterm"NAME="AUTOID-10576"></A><ACLASS="indexterm"NAME="AUTOID-10579"></A>[If your shell has interactive command-line editing, like the<SPANCLASS="link">Korn shell (<ACLASS="linkend"HREF="ch11_13.htm"TITLE="Shell Command-Line Editing ">11.13</A>)</SPAN>does, the technique here can still be useful.As Mike says, you might want to save the script and use it later.-JP]</P><PCLASS="para">Shell scripts are often handy, even if you never intend to writesoftware. One problem that most users face is typing acomplicated command correctly. For example, let's say you need totype the following monstrosity:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>soelim a.ms b.ms | pic | eqn | tbl | troff -ms -a | more</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">(This isn't unrealistic; I've typed this particular command a few times.)Rather than spend all that time typing, then backspacing to fix someerror, then typing some more, then backspacing again, you can create avery simple "throwaway" shell script with your favorite editor:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen"># shell script "foo" for one-time usesoelim a.ms b.ms | pic | eqn | tbl | troff -ms -a -rz1 | more</PRE></BLOCKQUOTE></P><PCLASS="para">Use your editor to play with the script until the command looksright - any half-competent text editor will be much easier to work withthan the "raw" command line. Then execute it like this:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>sh foo</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">If you don't think you'll need this command again, you can delete thefile - or use a <SPANCLASS="link">temporary file (<ACLASS="linkend"HREF="ch21_03.htm"TITLE="Unique Names for Temporary Files ">21.3</A>)</SPAN>in the first place.But before you use <EMCLASS="emphasis">rm</EM>, think: most things that you doonce, you'll need to do again. Give it an intelligent name, and save itin your<SPANCLASS="link"><EMCLASS="emphasis">bin</EM> directory (<ACLASS="linkend"HREF="ch04_02.htm"TITLE="A bin Directory for Your Programs and Scripts ">4.2</A>)</SPAN>.You're now a shell programmer.</P><PCLASS="para">This is also a great idea for complex sequences of commands.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">ML</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="ch09_14.htm"TITLE="9.14 Using Here Documents for Form Letters, etc. "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 9.14 Using Here Documents for Form Letters, etc. "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="ch09_16.htm"TITLE="9.16 Command Substitution "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 9.16 Command Substitution "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">9.14 Using Here Documents for Form Letters, etc. </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">9.16 Command Substitution </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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