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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 1] 1.12 What Makes a Shell Script? </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="1998-08-04T21:31:10Z"><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="ch01_01.htm"TITLE="1. Introduction"><LINKREL="prev"HREF="ch01_11.htm"TITLE="1.11 How the Shell Executes Other Commands "><LINKREL="next"HREF="ch01_13.htm"TITLE="1.13 Why Fundamentals Are Important "></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="ch01_11.htm"TITLE="1.11 How the Shell Executes Other Commands "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 1.11 How the Shell Executes Other Commands "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 1<BR>Introduction</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch01_13.htm"TITLE="1.13 Why Fundamentals Are Important "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 1.13 Why Fundamentals Are Important "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-1033">1.12 What Makes a Shell Script? </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-1290"></A>A shell script is just an<SPANCLASS="link">ASCII file (<ACLASS="linkend"HREF="glossary.htm#UPT-ART-1010"TITLE="Glossary">52.9</A>)</SPAN>containing a saved sequence of commands.</P><PCLASS="para">If you were to store a list of commands in a file for one-time use, you couldexecute it by typing:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>sh <CODECLASS="replaceable"><I>mycommands</I></CODE></B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">where <CODECLASS="replaceable"><I>mycommands</I></CODE> is the name of the file containing thelist of commands. This would tell the shell to treat thefile as a list of commands to be executed.</P><PCLASS="para">But there's a better way to tell the shell to execute thecontents of a file, and that is to make the fileexecutable with the<SPANCLASS="link"><EMCLASS="emphasis">chmod</EM> (<ACLASS="linkend"HREF="ch22_07.htm"TITLE="Using chmod to Change File Permission ">22.7</A>)</SPAN>command:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>chmod +x <CODECLASS="replaceable"><I>mycommands</I></CODE></B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">Then, all you have to do to execute the script is type itsname. (To make it even easier to use, you should<SPANCLASS="link"> store it in a personal <EMCLASS="emphasis">bin</EM> directory and add the <EMCLASS="emphasis">bin</EM> to your search path .) (<ACLASS="linkend"HREF="ch08_07.htm"TITLE="Setting Your Search Path ">8.7</A>)</SPAN></P><PCLASS="para">Of course, in either case, all of the lines in the file need tobe meaningful to the shell! If you accidentally made a letter to yourmother executable, and tried to run it as a shell script, you'dgeterror messages like this, containing the first word ofeach line in the letter:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">letter: Dear: not found</PRE></BLOCKQUOTE></P><PCLASS="para">The shell would try to interpret that word as a command, andreport back that it doesn't know any command by that name.</P><PCLASS="para">Also, to really make good use of shell scripts, you need tounderstand<SPANCLASS="link">how to pass arguments to a script (<ACLASS="linkend"HREF="ch44_15.htm"TITLE="Handling Command-Line Arguments in Shell Scripts ">44.15</A>)</SPAN>and<SPANCLASS="link">how to use some simple programming constructs (<ACLASS="linkend"HREF="ch01_05.htm"TITLE="Anyone Can Program the Shell ">1.5</A>)</SPAN>.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">TOR</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="ch01_11.htm"TITLE="1.11 How the Shell Executes Other Commands "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 1.11 How the Shell Executes Other Commands "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="ch01_13.htm"TITLE="1.13 Why Fundamentals Are Important "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 1.13 Why Fundamentals Are Important "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">1.11 How the Shell Executes Other Commands </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">1.13 Why Fundamentals Are Important </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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