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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 41] 41.7 Reading Verrrry Long Lines from the Terminal </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="1998-08-04T21:52:01Z"><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="ch41_01.htm"TITLE="41. Terminal and Serial Line Settings"><LINKREL="prev"HREF="ch41_06.htm"TITLE="41.6 Using sleep to Keep Port Settings "><LINKREL="next"HREF="ch41_08.htm"TITLE="41.8 ptys and Window Systems "></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="ch41_06.htm"TITLE="41.6 Using sleep to Keep Port Settings "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 41.6 Using sleep to Keep Port Settings "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 41<BR>Terminal and Serial Line Settings</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch41_08.htm"TITLE="41.8 ptys and Window Systems "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 41.8 ptys and Window Systems "BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-0338">41.7 Reading Verrrry Long Lines from the Terminal </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-45852"></A>Sometimes you can have a very long line of input that you want to writeto a file.It might come from your personal computer, a device hooked to yourterminal, or just an especially long set of characters that you have totype on the keyboard.Normally the UNIX<SPANCLASS="link">terminal driver (<ACLASS="linkend"HREF="ch42_01.htm#UPT-ART-1142"TITLE="Making Sense Out of the Terminal Mess ">42.1</A>)</SPAN>holds all characters you type until itsees a line terminator or interrupt character.Most buffers have room for 256 characters.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-45857"></A><ACLASS="indexterm"NAME="AUTOID-45860"></A>If you're typing the characters at the keyboard, there's an easy fix:Hit CTRL-d every 200 characters or so to flush the input buffer.You won't be able to backspace before that point, but the shell willread everything in.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-45864"></A><ACLASS="indexterm"NAME="AUTOID-45867"></A><ACLASS="indexterm"NAME="AUTOID-45869"></A>Or, to make UNIX pass each character it reads without buffering, use<SPANCLASS="link"><EMCLASS="emphasis">stty</EM> (<ACLASS="linkend"HREF="ch41_03.htm"TITLE="Find Out Terminal Settings with stty ">41.3</A>)</SPAN>to set your terminal to <EMCLASS="emphasis">cbreak</EM> (or <EMCLASS="emphasis">non-canonical</EM>) input mode.For example:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">% <CODECLASS="userinput"><B>stty cbreak</B></CODE>% <CODECLASS="userinput"><B>cat > file</B></CODE><CODECLASS="replaceable"><I>enter the very long line.........</I></CODE><KBDCLASS="keycap">[CTRL-c]</KBD>% <CODECLASS="userinput"><B>stty -cbreak</B></CODE></PRE></BLOCKQUOTE></P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-45883"></A>On System V, start with <CODECLASS="literal">stty -icanon</CODE> and end with<CODECLASS="literal">stty icanon</CODE>.</P><PCLASS="para">While you're in <EMCLASS="emphasis">cbreak</EM> mode, special keys like BACKSPACE or DELETEwon't be processed; they'll be stored in the file.Typing CTRL-dwill not make <EMCLASS="emphasis">cat</EM> quit.To quit, kill <EMCLASS="emphasis">cat</EM> by pressing your normal interrupt key - say, CTRL-c.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-45893"></A>(If you accidentally type a backspace or press RETURNwhen you didn'twant to, you can see those characters in the file with the octal dump command,<SPANCLASS="link"><EMCLASS="emphasis">od</EM> (<ACLASS="linkend"HREF="ch25_07.htm"TITLE="Show Non-Printing Characters with cat -v or od -c ">25.7</A>)</SPAN>,and its <EMCLASS="emphasis">-c</EM> option.Filter them out with<SPANCLASS="link"><EMCLASS="emphasis">tr -d</EM> (<ACLASS="linkend"HREF="ch35_11.htm"TITLE="Hacking on Characters with tr ">35.11</A>)</SPAN>or a text editor (the GNU<SPANCLASS="link">Emacs (<ACLASS="linkend"HREF="ch32_01.htm#UPT-ART-5540"TITLE="Emacs: The Other Editor ">32.1</A>)</SPAN>editorcan handle very long lines).)</P><PCLASS="para">One more problem: if you use a shell with<SPANCLASS="link">built-in command line editing (<ACLASS="linkend"HREF="ch11_13.htm"TITLE="Shell Command-Line Editing ">11.13</A>)</SPAN>and/or<SPANCLASS="link">filename completion (<ACLASS="linkend"HREF="ch09_08.htm"TITLE="Filename Completion: Faster Filename Typing ">9.8</A>)</SPAN>,they might cause you trouble because they use <EMCLASS="emphasis">stty</EM>-like commandsto let you edit. In that case, start a plain Bourne shell (type<EMCLASS="emphasis">sh</EM> or <EMCLASS="emphasis">/bin/sh</EM>) before you give the <EMCLASS="emphasis">stty</EM> command.</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="ch41_06.htm"TITLE="41.6 Using sleep to Keep Port Settings "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 41.6 Using sleep to Keep Port Settings "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="ch41_08.htm"TITLE="41.8 ptys and Window Systems "><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 41.8 ptys and Window Systems "BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">41.6 Using sleep to Keep Port Settings </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">41.8 ptys and Window Systems </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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