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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 35] 35.20 Quick Reference: uniq </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="1998-08-04T21:48:26Z"><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="ch35_01.htm"TITLE="35. You Can't Quite Call This Editing"><LINKREL="prev"HREF="ch35_19.htm"TITLE="35.19 Joining Lines with join "><LINKREL="next"HREF="ch35_21.htm"TITLE="35.21 Using IFS to Split Strings "></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="ch35_19.htm"TITLE="35.19 Joining Lines with join "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 35.19 Joining Lines with join "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 35<BR>You Can't Quite Call This Editing</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch35_21.htm"TITLE="35.21 Using IFS to Split Strings "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 35.21 Using IFS to Split Strings "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-2910">35.20 Quick Reference: uniq </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-41217"></A><ACLASS="indexterm"NAME="AUTOID-41219"></A><EMCLASS="emphasis">uniq</EM> is used to remove duplicate adjacent lines from a sortedfile, sending one copy of each line to standard output or to a secondfile, if one is specified on the command line.</P><BLOCKQUOTECLASS="note"><PCLASS="para"><STRONG>NOTE:</STRONG> Be warned:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>uniq file1 file2</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">will not print the unique lines from both <EMCLASS="emphasis">file1</EM> and <EMCLASS="emphasis">file2</EM>to standard output!It will replace the contents of <EMCLASS="emphasis">file2</EM> withthe unique lines from <EMCLASS="emphasis">file1</EM>.</P></BLOCKQUOTE><PCLASS="para"><EMCLASS="emphasis">uniq</EM> is often used as a<SPANCLASS="link">filter (<ACLASS="linkend"HREF="ch01_30.htm"TITLE="Redirecting Input and Output ">1.30</A>)</SPAN>.See also<SPANCLASS="link"><EMCLASS="emphasis">comm</EM> (<ACLASS="linkend"HREF="ch28_12.htm"TITLE="Comparing Two Files with comm ">28.12</A>)</SPAN>,<SPANCLASS="link"><EMCLASS="emphasis">sort</EM> (<ACLASS="linkend"HREF="ch36_01.htm#UPT-ART-7640"TITLE="Putting Things in Order ">36.1</A>)</SPAN>,and especially<SPANCLASS="link"><EMCLASS="emphasis">sort -u</EM> (<ACLASS="linkend"HREF="ch36_06.htm"TITLE="Miscellaneous sort Hints ">36.6</A>)</SPAN>.</P><PCLASS="para"><EMCLASS="emphasis">options</EM></P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">-c Print each line once, counting instances of each.-d Print duplicate lines once, but no unique lines.-u Print only unique lines (no copy of duplicate entries is kept).-<EMCLASS="emphasis">n</EM> Ignore first <EMCLASS="emphasis">n</EM> fields of a line. Fields are separated by spacesor by tabs.+<EMCLASS="emphasis">n</EM> Ignore first <EMCLASS="emphasis">n</EM> characters of a field.</PRE></BLOCKQUOTE></P><PCLASS="para">You can specify only one of the options <CODECLASS="userinput"><B>-c</B></CODE>, <CODECLASS="userinput"><B>-d</B></CODE>, or <CODECLASS="userinput"><B>-u</B></CODE>. </P><PCLASS="para"><EMCLASS="emphasis">Examples</EM></P><PCLASS="para">To send only one copy of each line from <CODECLASS="userinput"><B>list</B></CODE> to outputfile <CODECLASS="userinput"><B>list.new</B></CODE>:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen"><CODECLASS="literal">uniq list list.new</CODE></PRE></BLOCKQUOTE></P><PCLASS="para">To show which names appear more than once:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen"><CODECLASS="literal">sort names | uniq -d</CODE></PRE></BLOCKQUOTE></P><PCLASS="para">To show which lines appear exactly three times:</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch27_01.htm"TITLE="27.1 Different Versions of grep ">grep</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen"><CODECLASS="literal">sort names | uniq -c | </CODE>grep<CODECLASS="literal"> " 3 "</CODE></PRE></TD></TR></TABLE></P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">DG</SPAN> <SPANCLASS="bibliomisc">from O'Reilly & Associates' <CITECLASS="citetitle">UNIX in a Nutshell (SVR4/Solaris)</CITE></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="ch35_19.htm"TITLE="35.19 Joining Lines with join "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 35.19 Joining Lines with join "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="ch35_21.htm"TITLE="35.21 Using IFS to Split Strings "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 35.21 Using IFS to Split Strings "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">35.19 Joining Lines with join </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">35.21 Using IFS to Split Strings </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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