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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 4] 4.10 Find All Command Versions with whereiz </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="1998-08-04T21:32:46Z"><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="ch04_01.htm"TITLE="4. Organizing Your Home Directory"><LINKREL="prev"HREF="ch04_09.htm"TITLE="4.9 Setting Up vi with the .exrc File "><LINKREL="next"HREF="ch05_01.htm"TITLE="5. Setting Up Your Terminal"></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="ch04_09.htm"TITLE="4.9 Setting Up vi with the .exrc File "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 4.9 Setting Up vi with the .exrc File "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 4<BR>Organizing Your Home Directory</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="CHAPTER"HREF="ch05_01.htm"TITLE="5. Setting Up Your Terminal"><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 5. Setting Up Your Terminal"BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-4660">4.10 Find All Command Versions with whereiz </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-4683"></A><ACLASS="indexterm"NAME="AUTOID-4685"></A><ACLASS="indexterm"NAME="AUTOID-4688"></A><ACLASS="indexterm"NAME="AUTOID-4691"></A><ACLASS="indexterm"NAME="AUTOID-4693"></A>To get the absolute pathname of a command, Korn shell users can run<EMCLASS="emphasis">whence</EM>.<EMCLASS="emphasis">bash</EM> users have <EMCLASS="emphasis">type</EM>.<ACLASS="indexterm"NAME="AUTOID-4699"></A>On other shells, use<SPANCLASS="link"><EMCLASS="emphasis">which</EM> (<ACLASS="linkend"HREF="ch50_08.htm"TITLE="Which Version Am I Using? ">50.8</A>)</SPAN>.<ACLASS="indexterm"NAME="AUTOID-4703"></A>But those will only show the first directory in your<SPANCLASS="link"><EMCLASS="emphasis">PATH</EM> (<ACLASS="linkend"HREF="ch06_04.htm"TITLE="The PATH Environment Variable ">6.4</A>)</SPAN>with that command.If you want to find other commands with the same name in other directories,the standard <EMCLASS="emphasis">which</EM> won't show them to you.(The <EMCLASS="emphasis">which</EM> on the CD-ROM will - if you use its <EMCLASS="emphasis"> - a</EM>option.So will the <EMCLASS="emphasis">bash</EM> command <EMCLASS="emphasis">type -all</EM>.)<EMCLASS="emphasis">whereiz</EM> will:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>which grep</B></CODE>/usr/bin/grep% <CODECLASS="userinput"><B>whereiz grep</B></CODE>/usr/bin/grep /usr/5bin/grep</PRE></BLOCKQUOTE></P><PCLASS="para">On my system, the <EMCLASS="emphasis">/usr/bin</EM> directory holds a Berkeley-like version of acommand.The <EMCLASS="emphasis">/usr/5bin</EM> directory holds System V versions.<EMCLASS="emphasis">/usr/bin</EM> is first in my path, but it's good to know if there'salso a System V version.<EMCLASS="emphasis">whereiz</EM> also lets you see if there are both local and system versions ofthe same command in your path.</P><PCLASS="para">Here's the script.The name ends in a <EMCLASS="emphasis">z</EM> because many UNIX versions already have a<SPANCLASS="link"><EMCLASS="emphasis">whereis</EM> (<ACLASS="linkend"HREF="ch50_05.htm"TITLE="whereis: Finding Where a Command Is Located ">50.5</A>)</SPAN>command.</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"> <ACLASS="co"HREF="ch44_09.htm"TITLE="44.9 Testing Your Success ">&&</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen"> #! /bin/sh# COMMAND THAT TESTS FOR EXECUTABLE FILES... SYSTEM-DEPENDENT:testx="test -x"# REPLACE NULL FIELD IN $PATH WITH A .fixpath="`echo $PATH | sed \ -e 's/^:/.:/' \ -e 's/::/:.:/g' \ -e 's/:$/:./'`"IFS=": " # SET $IFS (COLON, SPACE, TAB) FOR PARSING $PATHfor commanddo where="" # ZERO OUT $where # IF DIRECTORY HAS EXECUTABLE FILE, ADD IT TO LIST: for direc in $fixpath do $testx $direc/$command && where="$where $direc/$command" done case "$where" in ?*) echo $where ;; # IF CONTAINS SOMETHING, OUTPUT IT esacdone</PRE></TD></TR></TABLE></P><PCLASS="para">The<ACLASS="indexterm"NAME="AUTOID-4731"></A><SPANCLASS="link"><EMCLASS="emphasis">sed</EM> (<ACLASS="linkend"HREF="ch34_24.htm"TITLE="Quick Reference: sed ">34.24</A>)</SPAN>command "fixes" your <EMCLASS="emphasis">PATH</EM>.It replaces a null directory name (<CODECLASS="literal">::</CODE> in the middle of the<EMCLASS="emphasis">PATH</EM> or a single <CODECLASS="literal">:</CODE> at the start or end of the <EMCLASS="emphasis">PATH</EM>),which stands for the current directory.The null member is changed to the<SPANCLASS="link">relative pathname for the current directory, a dot (<ACLASS="linkend"HREF="ch01_21.htm"TITLE="Making Pathnames ">1.21</A>)</SPAN>,so the <EMCLASS="emphasis">direc</EM> shell variable in the loop won't be empty.In line 12, the double quotes (<CODECLASS="literal">""</CODE>) have colon, space, and tabcharacters between them.<ACLASS="indexterm"NAME="AUTOID-4744"></A>This sets the<SPANCLASS="link"><EMCLASS="emphasis">IFS</EM> (<ACLASS="linkend"HREF="ch35_21.htm"TITLE="Using IFS to Split Strings ">35.21</A>)</SPAN>variable to split the "fixed" search path, at the colon<ACLASS="indexterm"NAME="AUTOID-4748"></A>characters,into separate directoriesduring the<SPANCLASS="link"><EMCLASS="emphasis">for</EM> loop (<ACLASS="linkend"HREF="ch44_16.htm"TITLE="Handling Command-Line Arguments with a for Loop ">44.16</A>)</SPAN>.That's a useful way to handle any colon-separated list.<ACLASS="indexterm"NAME="AUTOID-4753"></A><ACLASS="indexterm"NAME="AUTOID-4754"></A></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="ch04_09.htm"TITLE="4.9 Setting Up vi with the .exrc File "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 4.9 Setting Up vi with the .exrc File "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="CHAPTER"HREF="ch05_01.htm"TITLE="5. 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