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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 27] 27.15 Narrowing a Search Quickly </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="1998-08-04T21:44:32Z"><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="ch27_01.htm"TITLE="27. Searching Through Files"><LINKREL="prev"HREF="ch27_14.htm"TITLE="27.14 Compound Searches "><LINKREL="next"HREF="ch27_16.htm"TITLE="27.16 Faking Case-Insensitive Searches "></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="ch27_14.htm"TITLE="27.14 Compound Searches "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 27.14 Compound Searches "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 27<BR>Searching Through Files</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch27_16.htm"TITLE="27.16 Faking Case-Insensitive Searches "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 27.16 Faking Case-Insensitive Searches "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-0018">27.15 Narrowing a Search Quickly </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-30722"></A><ACLASS="indexterm"NAME="AUTOID-30726"></A>If you're searching a long file to find a particularword or name, or you're running a program like <EMCLASS="emphasis">ls -l</EM> and you want tofilter some lines, here's a quick way to narrow down the search.As an example, say your phone file has 20,000 lines like these:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">Smith, Nancy:MFG:50 Park Place:Huntsville:(205)234-5678</PRE></BLOCKQUOTE></P><PCLASS="para">and you want to find someone named Nancy. When you see moreinformation, you know you can find which of the Nancys she is:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>grep Nancy phones</B></CODE><ICLASS="lineannotation">...150 lines of names...</I></PRE></BLOCKQUOTE></P><PCLASS="para">Use the C shell's<SPANCLASS="link">history mechanism (<ACLASS="linkend"HREF="ch11_02.htm"TITLE="History in a Nutshell ">11.2</A>)</SPAN>and<SPANCLASS="link"><EMCLASS="emphasis">sed</EM> (<ACLASS="linkend"HREF="ch34_24.htm"TITLE="Quick Reference: sed ">34.24</A>)</SPAN>to cut out lines youdon't want.For example, about a third of the Nancys are in Huntsville, and you know shedoesn't work there:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>!! | sed -e /Huntsville/d</B></CODE>grep Nancy phones | sed -e /Huntsville/d<ICLASS="lineannotation">...100 lines of names...</I></PRE></BLOCKQUOTE></P><PCLASS="para">The shell shows the command it's executing: the previous command (<CODECLASS="literal">!!</CODE>)piped to <EMCLASS="emphasis">sed</EM>, which deletes lines in the <EMCLASS="emphasis">grep</EM>output that have the word <EMCLASS="emphasis">Huntsville</EM>.</P><PCLASS="para">Okay.You know Nancy doesn't work in the MFG or SLS groups,so delete those lines, too:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>!! -e /MFG/d -e /SLS/d</B></CODE>grep Nancy phones | sed -e /Huntsville/d -e /MFG/d -e /SLS/d<ICLASS="lineannotation">...20 lines of names...</I></PRE></BLOCKQUOTE></P><PCLASS="para">Keep using <CODECLASS="literal">!!</CODE> to repeat the previous command line, and addingmore <EMCLASS="emphasis">sed</EM> expressions, until the list gets short enough.The same thing works for other commands - when you're huntingfor errorsin<SPANCLASS="link"><EMCLASS="emphasis">uulog</EM> (<ACLASS="linkend"HREF="ch01_33.htm"TITLE="UNIX Networking and Communications ">1.33</A>)</SPAN>output, for example, and you want to skip lines with<CODECLASS="literal">SUCCEEDED</CODE> and <CODECLASS="literal">OK</CODE>:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>uulog | sed -e /SUCCEEDED/d -e /OK/d</B></CODE>...</PRE></BLOCKQUOTE></P><PCLASS="para">If the matching pattern has anything but letters and numbers in it, you'llhave to understand<SPANCLASS="link">shell quoting (<ACLASS="linkend"HREF="ch08_14.htm"TITLE="Bourne Shell Quoting ">8.14</A>)</SPAN>and <EMCLASS="emphasis">sed</EM><SPANCLASS="link">regular expressions (<ACLASS="linkend"HREF="ch26_04.htm"TITLE="Using Metacharacters in Regular Expressions ">26.4</A>)</SPAN>.Most times, though, this quick-and-dirty way works just fine.</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="ch27_14.htm"TITLE="27.14 Compound Searches "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 27.14 Compound Searches "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="ch27_16.htm"TITLE="27.16 Faking Case-Insensitive Searches "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 27.16 Faking Case-Insensitive Searches "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">27.14 Compound Searches </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">27.16 Faking Case-Insensitive Searches </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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