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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 44] 44.6 Pattern Matching in case Statements </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="1998-08-04T21:53:37Z"><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="ch44_01.htm"TITLE="44. Shell Programming for the Uninitiated"><LINKREL="prev"HREF="ch44_05.htm"TITLE="44.5 Test String Values with Bourne Shell case "><LINKREL="next"HREF="ch44_07.htm"TITLE="44.7 Exit Status of UNIX Processes "></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="ch44_05.htm"TITLE="44.5 Test String Values with Bourne Shell case "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 44.5 Test String Values with Bourne Shell case "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 44<BR>Shell Programming for the Uninitiated</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch44_07.htm"TITLE="44.7 Exit Status of UNIX Processes "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 44.7 Exit Status of UNIX Processes "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-7100">44.6 Pattern Matching in case Statements </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-50481"></A><ACLASS="indexterm"NAME="AUTOID-50484"></A><ACLASS="indexterm"NAME="AUTOID-50487"></A><ACLASS="indexterm"NAME="AUTOID-50490"></A><ACLASS="indexterm"NAME="AUTOID-50493"></A>A<SPANCLASS="link"><EMCLASS="emphasis">case</EM> statement (<ACLASS="linkend"HREF="ch44_05.htm"TITLE="Test String Values with Bourne Shell case ">44.5</A>)</SPAN>is good at string pattern matching.Its "wildcard" pattern-matching metacharacters work like the<SPANCLASS="link">filename wildcards (<ACLASS="linkend"HREF="ch01_16.htm"TITLE="Wildcards ">1.16</A>)</SPAN>in the shell, with a few twists.Here are some examples:</P><DLCLASS="variablelist"><DTCLASS="term"><CODECLASS="literal">?)</CODE></DT><DDCLASS="listitem"><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-50505"></A>Matches a string with exactly one character like <CODECLASS="literal">a</CODE>,<CODECLASS="literal">3</CODE>, <CODECLASS="literal">!</CODE>, and so on.</P></DD><DTCLASS="term"><CODECLASS="literal">?*)</CODE></DT><DDCLASS="listitem"><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-50516"></A><ACLASS="indexterm"NAME="AUTOID-50519"></A><ACLASS="indexterm"NAME="AUTOID-50522"></A>Matches a string with one or more characters (a non-emptystring).</P></DD><DTCLASS="term"><CODECLASS="literal">[yY]|[yY][eE][sS])</CODE></DT><DDCLASS="listitem"><PCLASS="para">Matches <CODECLASS="literal">y</CODE>, <CODECLASS="literal">Y</CODE> or <CODECLASS="literal">yes</CODE>, <CODECLASS="literal">YES</CODE>,<CODECLASS="literal">YeS</CODE>, etc. The <CODECLASS="literal">|</CODE> means "or."</P></DD><DTCLASS="term"><CODECLASS="literal">/*/*[0-9])</CODE></DT><DDCLASS="listitem"><PCLASS="para">Matches a file pathname, like<EMCLASS="emphasis">/xxx/yyy/somedir/file2</EM>, that starts with a slash, contains atleast one more slash, and ends with a digit.</P></DD><DTCLASS="term"><CODECLASS="literal">'What now?')</CODE></DT><DDCLASS="listitem"><PCLASS="para">Matches the pattern <CODECLASS="literal">What now?</CODE>.The<SPANCLASS="link">quotes (<ACLASS="linkend"HREF="ch08_14.htm"TITLE="Bourne Shell Quoting ">8.14</A>)</SPAN>tell the shell to treat the string literally: not to break it atthe space and not to treat the <CODECLASS="literal">?</CODE> as a wildcard.</P></DD><DTCLASS="term"><CODECLASS="literal">"$msgs")</CODE></DT><DDCLASS="listitem"><PCLASS="para">Matches the contents of the <EMCLASS="emphasis">msgs</EM> variable.The double quotes let the shell substitute the variable's value; thequotes also protext spaces and other special characters from theshell. For example, if <EMCLASS="emphasis">msgs</EM> contains <CODECLASS="literal">first next</CODE>, thenthis would match the same string, <CODECLASS="literal">first next</CODE>.</P></DD></DL><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="ch44_05.htm"TITLE="44.5 Test String Values with Bourne Shell case "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 44.5 Test String Values with Bourne Shell case "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="ch44_07.htm"TITLE="44.7 Exit Status of UNIX Processes "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 44.7 Exit Status of UNIX Processes "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">44.5 Test String Values with Bourne Shell case </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">44.7 Exit Status of UNIX Processes </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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