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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 23] 23.15 Using unlink to Remove a File with a Strange Name </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="1998-08-04T21:41:11Z"><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="ch23_01.htm"TITLE="23. Removing Files"><LINKREL="prev"HREF="ch23_14.htm"TITLE="23.14 Handling a Filename Starting with a Dash (-) "><LINKREL="next"HREF="ch23_16.htm"TITLE="23.16 Removing a Strange File by its I-number "></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="ch23_14.htm"TITLE="23.14 Handling a Filename Starting with a Dash (-) "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 23.14 Handling a Filename Starting with a Dash (-) "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 23<BR>Removing Files</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch23_16.htm"TITLE="23.16 Removing a Strange File by its I-number "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 23.16 Removing a Strange File by its I-number "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-0324">23.15 Using unlink to Remove a File with a Strange Name </A></H2><PCLASS="para">Some versions of UNIX have a lot of trouble with eight-bit filenames - thatis, filenames that contain non-<SPANCLASS="link">ASCII (<ACLASS="linkend"HREF="ch51_03.htm"TITLE="ASCII Characters: Listing and Getting Values ">51.3</A>)</SPAN>characters.<ACLASS="indexterm"NAME="AUTOID-25742"></A><ACLASS="indexterm"NAME="AUTOID-25744"></A><ACLASS="indexterm"NAME="AUTOID-25746"></A><ACLASS="indexterm"NAME="AUTOID-25748"></A>The<SPANCLASS="link"><EMCLASS="emphasis">ls -q</EM> (<ACLASS="linkend"HREF="ch16_14.htm"TITLE="Showing Non-Printable Characters in Filenames ">16.14</A>)</SPAN>command shows the non-ASCII characters as questionmarks (<CODECLASS="literal">?</CODE>), but usual tricks like<SPANCLASS="link"><EMCLASS="emphasis">rm -i *</EM> (<ACLASS="linkend"HREF="ch23_12.htm"TITLE="Using Wildcards to Delete Files with Strange Names ">23.12</A>)</SPAN>skip right over the file.You can at least see exactly what the filename is by using<ACLASS="indexterm"NAME="AUTOID-25757"></A><SPANCLASS="link"><EMCLASS="emphasis">od -c</EM> (<ACLASS="linkend"HREF="ch25_07.htm"TITLE="Show Non-Printing Characters with cat -v or od -c ">25.7</A>)</SPAN>to dump the current directory, using its relative pathname<SPANCLASS="link"><CODECLASS="literal">.</CODE> (dot) (<ACLASS="linkend"HREF="ch01_21.htm"TITLE="Making Pathnames ">1.21</A>)</SPAN>,character by character.(Note: some versions of UNIX have an<SPANCLASS="link"><EMCLASS="emphasis">ls -b</EM> (<ACLASS="linkend"HREF="ch16_14.htm"TITLE="Showing Non-Printable Characters in Filenames ">16.14</A>)</SPAN>option that will do the samething as <EMCLASS="emphasis">od -c</EM>, but a lot more easily.)</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>ls -q</B></CODE> ????afilebfile% <CODECLASS="userinput"><B>rm -i *</B></CODE>afile: ? <CODECLASS="userinput"><B>n</B></CODE>bfile: ? <CODECLASS="userinput"><B>n</B></CODE>% <CODECLASS="userinput"><B>od -c .</B></CODE> ...00..... \t 360 207 005 254 \0 \0 \0 \0 ...</PRE></BLOCKQUOTE></P><PCLASS="para">If you can move all the other files out of the directory, then you'llprobably be able to remove the leftover file and directory with<SPANCLASS="link"><EMCLASS="emphasis">rm -rf</EM> (<ACLASS="linkend"HREF="ch23_17.htm"TITLE="Problems Deleting Directories ">23.17</A>, <ACLASS="linkend"HREF="ch23_10.htm"TITLE="Deletion with Prejudice: rm -f ">23.10</A>)</SPAN>.Moving files and removing the directory is a bad idea, though, if thisis an important system directory like <EMCLASS="emphasis">/bin</EM>.</P><PCLASS="para">Otherwise, if you can find the filename in the <EMCLASS="emphasis">od</EM> listing of thedirectory (it will probably end with a series of NUL characters,like <CODECLASS="literal">\0 \0 \0</CODE>...), you might be able to remove it directlyby using the system call <EMCLASS="emphasis">unlink</EM>(2) in Perl.Put a backslash (<CODECLASS="literal">\</CODE>) before each of the octal bytes shown inthe <EMCLASS="emphasis">od</EM> output:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">perl -e 'unlink("\t\360\207\005\254");'</PRE></BLOCKQUOTE></P><PCLASS="para">If you don't have Perl, write<SPANCLASS="link">a little C program (<ACLASS="linkend"HREF="ch52_08.htm"TITLE="Building Programs from Source Code ">52.8</A>)</SPAN>:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>vi unlink.c</B></CODE> ...% <CODECLASS="userinput"><B>cat unlink.c</B></CODE>main(){ unlink("\t\360\207\005\254");}% <CODECLASS="userinput"><B>cc unlink.c</B></CODE>% <CODECLASS="userinput"><B>./a.out</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">Another <EMCLASS="emphasis">ls</EM> will tell you whether your program worked (thereprobably won't be any error messages if it doesn't work).</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="ch23_14.htm"TITLE="23.14 Handling a Filename Starting with a Dash (-) "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 23.14 Handling a Filename Starting with a Dash (-) "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="ch23_16.htm"TITLE="23.16 Removing a Strange File by its I-number "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 23.16 Removing a Strange File by its I-number "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">23.14 Handling a Filename Starting with a Dash (-) </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">23.16 Removing a Strange File by its I-number </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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