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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 32] 32.9 Unset PWD Before Using Emacs </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="1998-08-04T21:46:38Z"><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="ch32_01.htm"TITLE="32. GNU Emacs"><LINKREL="prev"HREF="ch32_08.htm"TITLE="32.8 Rational Searches "><LINKREL="next"HREF="ch32_10.htm"TITLE="32.10 Inserting Binary Characters into Files "></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="ch32_08.htm"TITLE="32.8 Rational Searches "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 32.8 Rational Searches "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 32<BR>GNU Emacs</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch32_10.htm"TITLE="32.10 Inserting Binary Characters into Files "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 32.10 Inserting Binary Characters into Files "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-5547">32.9 Unset PWD Before Using Emacs </A></H2><PCLASS="para">I've seen a number of strange situations in which Emacs can't findfiles unless you type a<SPANCLASS="link">complete ("absolute") pathname (<ACLASS="linkend"HREF="ch01_21.htm"TITLE="Making Pathnames ">1.21</A>)</SPAN>,<ACLASS="indexterm"NAME="AUTOID-36059"></A><ACLASS="indexterm"NAME="AUTOID-36062"></A>starting fromthe root (<EMCLASS="emphasis">/</EM> ). When you try to "visit" a file, you'll get themessage <CODECLASS="literal">File not found and directory doesn't exist</CODE>.</P><PCLASS="para">In my experience, this usually means that the C shell's<SPANCLASS="link"><EMCLASS="emphasis">PWD</EM> environment variable (<ACLASS="linkend"HREF="ch06_03.htm"TITLE="Predefined Environment Variables ">6.3</A>)</SPAN>has gotten set incorrectly.There are a few(relatively pathological) ways of tricking the C shell into making amistake. More commonly though, I've seen a few systems on which theC shell sticks an extra slash into <EMCLASS="emphasis">PWD</EM>: that is, itsvalue will be something like <EMCLASS="emphasis">/home/mike//Mail</EM> rather than<EMCLASS="emphasis">/home/mike/Mail</EM>. UNIX doesn't care; it lets you stack up extraslashes without trouble. But Emacs interprets <EMCLASS="emphasis">//</EM> as the rootdirectory - that is, it discards everything to the left of the doubleslash. So if you're trying to edit the file<EMCLASS="emphasis">/home/mike//Mail/output.txt</EM>, Emacs will look for<EMCLASS="emphasis">/Mail/output.txt</EM>. Even if this file exists, it's not what youwant.[This also happens when Emacs is called from a (Bourne) shell scriptthat has changed its current directory without changing <EMCLASS="emphasis">PWD</EM>. -<EMCLASS="emphasis">JP</EM> ]</P><PCLASS="para">This problem is particularly annoying because the shell willautomatically reset <EMCLASS="emphasis">PWD</EM> every time you change directories - so theobvious solution, sticking <CODECLASS="literal">unsetenv PWD</CODE> in your <EMCLASS="emphasis">.cshrc</EM>file, doesn't do any good.</P><PCLASS="para">What will work is defining an <SPANCLASS="link">alias (<ACLASS="linkend"HREF="ch10_01.htm#UPT-ART-4930"TITLE="Creating Custom Commands ">10.1</A>)</SPAN>:</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch13_07.htm"TITLE="13.7 The () Subshell Operators ">(..)</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen">alias gmacs "(unsetenv PWD; emacs \!*)"</PRE></TD></TR></TABLE></P><PCLASS="para"> A better solution might be to switch to another shell that doesn'thave this problem. The Bourne shell (<EMCLASS="emphasis">sh</EM>) obviously doesn't,since it doesn't keep track of your current directory.</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="ch32_08.htm"TITLE="32.8 Rational Searches "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 32.8 Rational 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="ch32_10.htm"TITLE="32.10 Inserting Binary Characters into Files "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 32.10 Inserting Binary Characters into Files "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">32.8 Rational 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">32.10 Inserting Binary Characters into Files </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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