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<HTML><HEAD><TITLE>Installing Flex-2.5.4a</TITLE><METANAME="GENERATOR"CONTENT="Modular DocBook HTML Stylesheet Version 1.63"><LINKREL="HOME"TITLE="Linux From Scratch"HREF="../index.html"><LINKREL="UP"TITLE="Installing basic system software"HREF="../chapter06/chapter06.html"><LINKREL="PREVIOUS"TITLE="Installing Bash-2.05a"HREF="../chapter06/bash.html"><LINKREL="NEXT"TITLE="Installing File-3.36"HREF="../chapter06/file.html"></HEAD><BODYCLASS="sect1"BGCOLOR="#FFFFFF"TEXT="#000000"LINK="#0000FF"VLINK="#840084"ALINK="#0000FF"><DIVCLASS="NAVHEADER"><TABLEWIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><THCOLSPAN="3"ALIGN="center">Linux From Scratch: Version 3.1</TH></TR><TR><TDWIDTH="10%"ALIGN="left"VALIGN="bottom"><AHREF="../chapter06/bash.html">Prev</A></TD><TDWIDTH="80%"ALIGN="center"VALIGN="bottom">Chapter 6. Installing basic system software</TD><TDWIDTH="10%"ALIGN="right"VALIGN="bottom"><AHREF="../chapter06/file.html">Next</A></TD></TR></TABLE><HRALIGN="LEFT"WIDTH="100%"></DIV><DIVCLASS="sect1"><H1CLASS="sect1"><ANAME="ch06-flex">6.23. Installing Flex-2.5.4a</A></H1><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><FONTCOLOR="#000000"><PRECLASS="screen">Estimated build time: 1 minuteEstimated required disk space: 3MB</PRE></FONT></TD></TR></TABLE><DIVCLASS="sect2"><H2CLASS="sect2"><ANAME="AEN2427">6.23.1. Installation of Flex</A></H2><P>Install Flex by running the following commands:</P><P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><FONTCOLOR="#000000"><PRECLASS="screen"><TTCLASS="userinput"><B>./configure --prefix=/usr &&make &&make install</B></TT></PRE></FONT></TD></TR></TABLE></P><P>Some programs don't know about flex and try to find the lex program(flex is a (better) alternative for lex). So to please those fewprograms out there we'll create a lex script that calls flex and haveit emulate lex.</P><P>Create a new file <TTCLASS="filename">/usr/bin/lex</TT> by running thefollowing:</P><P><TABLEBORDER="0"BGCOLOR="#E0E0E0"WIDTH="100%"><TR><TD><FONTCOLOR="#000000"><PRECLASS="screen"><TTCLASS="userinput"><B>cat > /usr/bin/lex << "EOF"</B></TT>#!/bin/sh# Begin /usr/bin/lexexec /usr/bin/flex -l "$@"# End /usr/bin/lex<TTCLASS="userinput"><B>EOFchmod 755 /usr/bin/lex</B></TT></PRE></FONT></TD></TR></TABLE></P></DIV><DIVCLASS="sect2"><H2CLASS="sect2"><ANAME="AEN2440">6.23.2. Contents</A></H2><P>The Flex package contains the flex program</P></DIV><DIVCLASS="sect2"><H2CLASS="sect2"><ANAME="AEN2443">6.23.3. Description</A></H2><P>Flex is a tool for generating programs which recognize patterns in text. Pattern recognition is very useful in many applications. A user sets up rules what to look for and flex will make a program that looks for thosepatterns. The reason people use flex is that it is much easier to sets up rules for what to look for than to write the actual program that finds the text.</P></DIV><DIVCLASS="sect2"><H2CLASS="sect2"><ANAME="AEN2446">6.23.4. Dependencies</A></H2><P>Flex-2.5.4a needs the following to be installed:</P><PCLASS="literallayout"><br>sh from the bash package<br><br>ar from the binutils package<br>as from the binutils package<br>ld from the binutils package<br><br>bison from the bison package<br>yacc from the bison package<br><br>chmod from the fileutils package<br>cp from the fileutils package<br>ln from the fileutils package<br>mv from the fileutils package<br>rm from the fileutils package<br>touch from the fileutils package<br><br>cc from the gcc package<br><br>egrep from the grep package<br>grep from the grep package<br><br>make from the make package<br><br>sed from the sed package<br><br>dirname from the sh-utils package<br><br>cat from the textutils package<br>tr from the textutils package<br></P></DIV></DIV><DIVCLASS="NAVFOOTER"><HRALIGN="LEFT"WIDTH="100%"><TABLEWIDTH="100%"BORDER="0"CELLPADDING="0"CELLSPACING="0"><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top"><AHREF="../chapter06/bash.html">Prev</A></TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="../index.html">Home</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top"><AHREF="../chapter06/file.html">Next</A></TD></TR><TR><TDWIDTH="33%"ALIGN="left"VALIGN="top">Installing Bash-2.05a</TD><TDWIDTH="34%"ALIGN="center"VALIGN="top"><AHREF="../chapter06/chapter06.html">Up</A></TD><TDWIDTH="33%"ALIGN="right"VALIGN="top">Installing File-3.36</TD></TR></TABLE></DIV></BODY></HTML>⌨️ 快捷键说明
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