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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 17] 17.18 Using "Fast find"</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="1998-08-04T21:38:33Z"><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="ch17_01.htm"TITLE="17. Finding Files with find"><LINKREL="prev"HREF="ch17_17.htm"TITLE="17.17 Duplicating a Directory Tree (No Pathnames with find {} Operator)"><LINKREL="next"HREF="ch17_19.htm"TITLE="17.19 Finding Files (Much) Faster with a find Database "></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="ch17_17.htm"TITLE="17.17 Duplicating a Directory Tree (No Pathnames with find {} Operator)"><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 17.17 Duplicating a Directory Tree (No Pathnames with find {} Operator)"BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 17<BR>Finding Files with find</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch17_19.htm"TITLE="17.19 Finding Files (Much) Faster with a find Database "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 17.19 Finding Files (Much) Faster with a find Database "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-1620">17.18 Using "Fast find"</A></H2><PCLASS="para"><ACLASS="indexterm"NAME="UPT-ART-1620-IX-FAST-FIND"></A><ACLASS="indexterm"NAME="UPT-ART-1620-IX-FIND-COMMAND-FAST-FIND"></A>Berkeley added a handy feature to its <EMCLASS="emphasis">find</EM> command - if you give it a single argument, it will search a database for file ordirectory names that match.(If your system doesn't have this feature, see the <EMCLASS="emphasis">locate</EM> utility below.)For example, if you know there's a file named <EMCLASS="emphasis">MH.eps</EM> somewhere onthe computer but you don't know where, type:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find MH.eps</B></CODE>/nutshell/graphics/cover/MH.eps</PRE></BLOCKQUOTE></P><PCLASS="para">The database is usually rebuilt every night.So, it's not completely up-to-date, but it's usually close enough.If your system administrator has set this up, the database usually listsall files on the filesystem - although it may not list files indirectories that don't have world-access permission.If the database isn't set up at all, you'll get an error like<CODECLASS="literal">/usr/lib/find/find.codes: No such file or directory</CODE>.(If that's the case, you can set up a "fast <EMCLASS="emphasis">find</EM>" database yourself.Use GNU <EMCLASS="emphasis">locate</EM>, below, or seearticle<ACLASS="xref"HREF="ch17_19.htm"TITLE="Finding Files (Much) Faster with a find Database ">17.19</A>.)</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-19403"></A><ACLASS="indexterm"NAME="AUTOID-19406"></A>Unless you use wildcards, fast <EMCLASS="emphasis">find</EM> does a simple string search, like<SPANCLASS="link"><EMCLASS="emphasis">fgrep</EM> (<ACLASS="linkend"HREF="ch27_06.htm"TITLE="Fast grep Isn't ">27.6</A>)</SPAN>,through a list of<SPANCLASS="link">absolute pathnames (<ACLASS="linkend"HREF="ch14_02.htm"TITLE="Using Relative and Absolute Pathnames ">14.2</A>)</SPAN>.Here's an extreme example:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find bin</B></CODE>/bin/bin/ar .../home/robin/home/robin/afile/home/sally/bin ...</PRE></BLOCKQUOTE></P><PCLASS="para">You can cut down this output by piping it through<SPANCLASS="link"><EMCLASS="emphasis">grep</EM> (<ACLASS="linkend"HREF="ch27_01.htm#UPT-ART-7420"TITLE="Different Versions of grep ">27.1</A>)</SPAN>,<SPANCLASS="link"><EMCLASS="emphasis">sed</EM> (<ACLASS="linkend"HREF="ch34_24.htm"TITLE="Quick Reference: sed ">34.24</A>)</SPAN>,and so on.All the fast <EMCLASS="emphasis">find</EM> commands I've used have an undocumented feature, though:they can match<SPANCLASS="link">shell wildcards (<CODECLASS="literal">*</CODE>, <CODECLASS="literal">?</CODE>, <CODECLASS="literal">[]</CODE>) (<ACLASS="linkend"HREF="ch15_02.htm"TITLE="Filename Wildcards in a Nutshell ">15.2</A>)</SPAN>.If you use a wildcard on one end of the pattern, the search pattern isautomatically "anchored" to the opposite end of the string (the end where thewildcard isn't).The shell matches filenames in the same way.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-19427"></A>The difference between the shell's wildcard matching and fast <EMCLASS="emphasis">find</EM>'smatching is that the shell treats slashes (<CODECLASS="literal">/</CODE>) specially: youhave to type them as part of the expression.In fast <EMCLASS="emphasis">find</EM>, a wildcard matches slashes and any other character.When you use a wildcard, be sure to put quotes around the pattern so the shellwon't touch it.</P><PCLASS="para"> Here are some examples:</P><ULCLASS="itemizedlist"><LICLASS="listitem"><PCLASS="para">To find any pathname that ends with <EMCLASS="emphasis">bin</EM>:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find '*bin'</B></CODE>/bin/home/robin/home/robin/bin ...</PRE></BLOCKQUOTE></P><PCLASS="para"></P></LI><LICLASS="listitem"><PCLASS="para">To find any pathname that ends with <EMCLASS="emphasis">/bin</EM> (a good way to find a file ordirectory named exactly <EMCLASS="emphasis">bin</EM>):</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find '*/bin'</B></CODE>/bin/home/robin/bin/usr/bin ...</PRE></BLOCKQUOTE></P><PCLASS="para"></P></LI><LICLASS="listitem"><PCLASS="para">Typing <CODECLASS="literal">find '*bin*'</CODE> is the same as typing <CODECLASS="literal">find bin</CODE>.</P></LI><LICLASS="listitem"><PCLASS="para">To match the files in a directory named <EMCLASS="emphasis">bin</EM>, but not the directoryitself, try something like:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find '*/bin/*'</B></CODE>/bin/ar/bin/cat .../home/robin/bin/prog</PRE></BLOCKQUOTE></P><PCLASS="para"></P></LI><LICLASS="listitem"><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-19463"></A><ACLASS="indexterm"NAME="AUTOID-19466"></A>To find the files in <EMCLASS="emphasis">/home</EM> whose names end with a tilde (<CODECLASS="literal">~</CODE>)(these are probably backup files from the Emacs editor):</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find '/home/*~'</B></CODE>/home/testfile~/home/allan/.cshrc~/home/allan/.login~/home/dave/.profile~ ...</PRE></BLOCKQUOTE></P><PCLASS="para">Notice that the fast <EMCLASS="emphasis">find</EM> asterisk matches "dot files," too.</P></LI><LICLASS="listitem"><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-19478"></A><ACLASS="indexterm"NAME="AUTOID-19481"></A>The <CODECLASS="literal">?</CODE> (question mark) and <CODECLASS="literal">[]</CODE> (square brackets) operatorswork, too.They're not quite as useful as they are in the shell because they matchthe slashes (<CODECLASS="literal">/</CODE>) in the pathnames.Here are a couple of quick examples: </P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>find '????'</B></CODE>/bin/etc/lib/src/sys/usr% <CODECLASS="userinput"><B>find '/[bel]??'</B></CODE>/bin/etc/lib</PRE></BLOCKQUOTE></P></LI></UL><TABLECLASS="para.programreference"BORDER="1"><TR><THVALIGN="TOP"><ACLASS="programreference"HREF="examples/index.htm"TITLE="locate">locate</A><BR></TH><TDVALIGN="TOP"><ACLASS="indexterm"NAME="AUTOID-19493"></A>Unfortunately, not all systems have fast find.Fortunately, the Free Software Foundation has <EMCLASS="emphasis">locate</EM>.It's similar to fast find, but<EMCLASS="emphasis">locate</EM> has an advantage: you can have multiple file databasesand you can search some or all of them.<EMCLASS="emphasis">Locate</EM> comes with a database building program.</TD></TR></TABLE><PCLASS="para">Because fast <EMCLASS="emphasis">find</EM> and <EMCLASS="emphasis">locate</EM> areso fast, they're worth trying to use whenever you can.Pipe the output to<SPANCLASS="link"><EMCLASS="emphasis">xargs</EM> (<ACLASS="linkend"HREF="ch09_21.htm"TITLE="Handle Too-Long Command Lines with xargs ">9.21</A>)</SPAN>and any other UNIX command,run a shell or <EMCLASS="emphasis">awk</EM> script to test its output - almost anything willbe faster than running a standard <EMCLASS="emphasis">find</EM>.For example, if you want a long listing of the files, here are two<EMCLASS="emphasis">find</EM> commands to do it:</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch16_08.htm"TITLE="16.8 The ls -d Option ">-d</A> <ACLASS="co"HREF="ch09_16.htm"TITLE="9.16 Command Substitution ">`...`</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen">% <CODECLASS="userinput"><B>ls -l `find <CODECLASS="replaceable"><I>whatever</I></CODE>`</B></CODE>% <CODECLASS="userinput"><B>find </B></CODE><CODECLASS="replaceable"><I>whatever </I></CODE><CODECLASS="userinput"><B>| xargs ls -ld</B></CODE></PRE></TD></TR></TABLE></P><PCLASS="para">There's one problem with that trick.The fast <EMCLASS="emphasis">find</EM> list may be built by <EMCLASS="emphasis">root</EM>,which can see all thefiles on the filesystem; your <EMCLASS="emphasis">ls -l</EM> commandmay not be able to access all files in the list.<ACLASS="indexterm"NAME="AUTOID-19519"></A><ACLASS="indexterm"NAME="AUTOID-19520"></A></P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- 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