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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 49] 49.5 Base Conversion Using cvtbase </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="1998-08-04T21:56:41Z"><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="ch49_01.htm"TITLE="49. Working with Numbers"><LINKREL="prev"HREF="ch49_04.htm"TITLE="49.4 bc's Sine and Cosine Are in Radians "><LINKREL="next"HREF="ch49_06.htm"TITLE="49.6 Quick Arithmetic with expr "></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="ch49_04.htm"TITLE="49.4 bc's Sine and Cosine Are in Radians "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 49.4 bc's Sine and Cosine Are in Radians "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 49<BR>Working with Numbers</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch49_06.htm"TITLE="49.6 Quick Arithmetic with expr "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 49.6 Quick Arithmetic with expr "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-9005">49.5 Base Conversion Using cvtbase </A></H2><TABLECLASS="para.programreference"BORDER="1"><TR><THVALIGN="TOP"><ACLASS="programreference"HREF="examples/index.htm"TITLE="cvtbase">cvtbase</A><BR></TH><TDVALIGN="TOP"><ACLASS="indexterm"NAME="AUTOID-58620"></A><ACLASS="indexterm"NAME="AUTOID-58622"></A>The <EMCLASS="emphasis">bc</EM> command can be used to <SPANCLASS="link">convert between different bases (<ACLASS="linkend"HREF="ch49_02.htm"TITLE="bc: Hexadecimal or Binary Conversion ">49.2</A>)</SPAN>,but an easier tool to use is <EMCLASS="emphasis">cvtbase</EM>.<EMCLASS="emphasis">cvtbase</EM>is designed specifically to convert from one format to another.For example, toconvert a decimal IP addressinto its hexadecimal equivalent:</TD></TR></TABLE><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>cvtbase d h</B></CODE><CODECLASS="userinput"><B>140.186.65.25</B></CODE>8c.ba.41.19</PRE></BLOCKQUOTE></P><PCLASS="para">The first argument, <CODECLASS="literal">d</CODE>, means that our input willbe in decimal form.The second argument, <CODECLASS="literal">h</CODE>, means thatwe want the input converted into hexadecimal.In general, the syntax for calling <EMCLASS="emphasis">cvtbase</EM> is:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">cvtbase <CODECLASS="replaceable"><I>input_base output_base</I></CODE></PRE></BLOCKQUOTE></P><PCLASS="para">where <EMCLASS="emphasis">input_base</EM> and <EMCLASS="emphasis">output_base</EM> are any of:</P><DLCLASS="variablelist"><DTCLASS="term"><CODECLASS="literal">d, D</CODE></DT><DDCLASS="listitem"><PCLASS="para">Decimal; i.e., digits <CODECLASS="literal">0</CODE> through <CODECLASS="literal">9</CODE>.</P></DD><DTCLASS="term"><CODECLASS="literal">x, h</CODE></DT><DDCLASS="listitem"><PCLASS="para">Hexadecimal (using lowercase); i.e., <CODECLASS="literal">0</CODE> through <CODECLASS="literal">9</CODE> and <CODECLASS="literal">a</CODE> through <CODECLASS="literal">f</CODE>.</P></DD><DTCLASS="term"><CODECLASS="literal">X, H</CODE></DT><DDCLASS="listitem"><PCLASS="para">Hexadecimal (using uppercase); i.e., <CODECLASS="literal">0</CODE> through <CODECLASS="literal">9</CODE> and <CODECLASS="literal">A</CODE> through <CODECLASS="literal">F</CODE>.</P></DD><DTCLASS="term"><CODECLASS="literal">o, O</CODE></DT><DDCLASS="listitem"><PCLASS="para">Octal; i.e., digits <CODECLASS="literal">0</CODE> through <CODECLASS="literal">7</CODE>.</P></DD><DTCLASS="term"><CODECLASS="literal">b, B</CODE></DT><DDCLASS="listitem"><PCLASS="para">Binary; i.e., digits <CODECLASS="literal">0</CODE> and <CODECLASS="literal">1</CODE>.</P></DD></DL><PCLASS="para">Any input characters that aren't in the specified set are sent through unchanged.In the example above, the dots (<CODECLASS="literal">.</CODE>)in the IP address are retained in the hexadecimal output.</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">LM</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="ch49_04.htm"TITLE="49.4 bc's Sine and Cosine Are in Radians "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 49.4 bc's Sine and Cosine Are in Radians "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="ch49_06.htm"TITLE="49.6 Quick Arithmetic with expr "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 49.6 Quick Arithmetic with expr "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">49.4 bc's Sine and Cosine Are in Radians </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">49.6 Quick Arithmetic with expr </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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