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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 25] 25.3 Using more to Page Through Files </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="1998-08-04T21:43:07Z"><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="ch25_01.htm"TITLE="25. Showing What's in a File"><LINKREL="prev"HREF="ch25_02.htm"TITLE="25.2 Four Ways to Skin a cat "><LINKREL="next"HREF="ch25_04.htm"TITLE='25.4 The "less" Pager: More than "more"'></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="ch25_02.htm"TITLE="25.2 Four Ways to Skin a cat "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.2 Four Ways to Skin a cat "BORDER="0"></A></TD><TDALIGN="CENTER"VALIGN="TOP"WIDTH="171"><B><FONTFACE="ARIEL,HELVETICA,HELV,SANSERIF"SIZE="-1">Chapter 25<BR>Showing What's in a File</FONT></B></TD><TDALIGN="RIGHT"VALIGN="TOP"WIDTH="172"><ACLASS="SECT1"HREF="ch25_04.htm"TITLE='25.4 The "less" Pager: More than "more"'><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT='Next: 25.4 The "less" Pager: More than "more"'BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-2610">25.3 Using more to Page Through Files </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-27238"></A><ACLASS="indexterm"NAME="AUTOID-27240"></A><ACLASS="indexterm"NAME="AUTOID-27244"></A><ACLASS="indexterm"NAME="AUTOID-27246"></A>The <EMCLASS="emphasis">more</EM> utility is light-years ahead of <SPANCLASS="link"><EMCLASS="emphasis">cat</EM> (<ACLASS="linkend"HREF="ch25_02.htm"TITLE="Four Ways to Skin a cat ">25.2</A>)</SPAN>.It lets you read files one page at a time. If you had only <EMCLASS="emphasis">cat</EM>and wanted to read long files, you'd have to read very fast or have aquick trigger finger (on <SPANCLASS="link">CTRL-s (<ACLASS="linkend"HREF="ch41_02.htm"TITLE="stty and All That Stuff ">41.2</A>)</SPAN>)to stop the text - or get used to reading thelast few lines of a file, and no more.In fact, even the most backward versions of <EMCLASS="emphasis">more</EM> are infinitelypreferable to <EMCLASS="emphasis">cat</EM> for reading a file - so much so that I don'tunderstand why anyone uses <EMCLASS="emphasis">cat</EM> for this purpose.[I <EMCLASS="emphasis">cat</EM> tiny files because I have <EMCLASS="emphasis">more</EM> and<SPANCLASS="link"><EMCLASS="emphasis">less</EM> (<ACLASS="linkend"HREF="ch25_04.htm"TITLE='The "less" Pager: More than "more"'>25.4</A>)</SPAN>set up to clear my screen (with the <EMCLASS="emphasis">-c</EM> option)before displaying a file. <EMCLASS="emphasis">-TC</EM> ]</P><PCLASS="para">When you start <EMCLASS="emphasis">more</EM>, it displays the first screen of the file.To move to the next page, press the space bar. You can continue to moveforward through the file by pressing the space bar or by pressing RETURN(which moves you forward one line). More recent versions of<EMCLASS="emphasis">more</EM> allow you to "back up" to previous pages in the file bytyping <CODECLASS="literal">b</CODE>.</P><PCLASS="para">Some other features:</P><ULCLASS="itemizedlist"><LICLASS="listitem"><PCLASS="para">If you list several files on the command line, you can type <CODECLASS="literal">:n</CODE> tomove to the next file and <CODECLASS="literal">:p</CODE> to move to the previous one.</P></LI><LICLASS="listitem"><PCLASS="para">You can get a "help" screen at any time by typing <CODECLASS="literal">h</CODE>.</P></LI><LICLASS="listitem"><PCLASS="para">You can jump from <EMCLASS="emphasis">more</EM> into the <EMCLASS="emphasis">vi</EM> editor by typing <CODECLASS="literal">v</CODE>.</P></LI><LICLASS="listitem"><PCLASS="para">You can search for a string by typing <CODECLASS="literal">/</CODE>, followed by the stringyou want. The search string can be a full <SPANCLASS="link">regular expression (<ACLASS="linkend"HREF="ch26_01.htm#UPT-ART-7844"TITLE="That's an Expression ">26.1</A>)</SPAN>.You can find the next occurrence of a string by typing <CODECLASS="literal">n</CODE>.</P></LI></UL><PCLASS="para">If you invoke <EMCLASS="emphasis">more</EM> with two or more files, it will display ashort header at the beginning of each file. This little nicety isstrangely useful. Let's say you want to print all of your <EMCLASS="emphasis">.h</EM>files with a single command, and you'd like some kind of label beforeeach file.You can<SPANCLASS="link">use <EMCLASS="emphasis">more</EM> to create the labels (<ACLASS="linkend"HREF="ch43_10.htm"TITLE="Filename Headers Above Files Without pr ">43.10</A>)</SPAN>for you:</P><PCLASS="para"><TABLECLASS="screen.co"BORDER="1"><TR><THVALIGN="TOP"><PRECLASS="calloutlist"><ACLASS="co"HREF="ch43_07.htm"TITLE="43.7 Quick-and-Dirty Formatting Before Printing ">pr</A> <ACLASS="co"HREF="ch43_02.htm"TITLE="43.2 Introduction to Printing on UNIX ">lpr</A> </PRE></TH><TDVALIGN="TOP"><PRECLASS="screen">% <CODECLASS="userinput"><B>more *.h | pr | lpr</B></CODE></PRE></TD></TR></TABLE></P><PCLASS="para">(When <EMCLASS="emphasis">more</EM> isn't writing to a terminal, it doesn't expect you to typeanything; it dumps all files to standard output.)</P><PCLASS="para"><EMCLASS="emphasis">more</EM> has a few defects:</P><ULCLASS="itemizedlist"><LICLASS="listitem"><PCLASS="para">Even the best versions can't back up while reading a pipe. So if you pipe the output from some command into <EMCLASS="emphasis">more</EM>,<CODECLASS="literal">b</CODE> won't work.</P></LI><LICLASS="listitem"><PCLASS="para">When you get to the end of the last file, <EMCLASS="emphasis">more</EM> quits. I guessthere's nothing wrong with this behavior, but I don't like it; I'drather have the chance to back up or move to an earlier file.</P></LI><LICLASS="listitem"><PCLASS="para">Some implementations of <EMCLASS="emphasis">more</EM> (System V) terminate ifyou search for a string that it can't find.</P></LI></UL><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-27312"></A><ACLASS="indexterm"NAME="AUTOID-27314"></A>A program called <SPANCLASS="link"><EMCLASS="emphasis">less</EM> (<ACLASS="linkend"HREF="ch25_04.htm"TITLE='The "less" Pager: More than "more"'>25.4</A>)</SPAN>less utilitysolves all of these problems.</P><PCLASS="para">[Some versions of System V support a somewhat equivalent programcalled <EMCLASS="emphasis">pg</EM> instead of <EMCLASS="emphasis">more</EM>.And some people like to lookat files with a read-only version of <EMCLASS="emphasis">vi</EM> called <EMCLASS="emphasis">view</EM>.I prefer <EMCLASS="emphasis">more</EM> or <EMCLASS="emphasis">less</EM>. <CODECLASS="literal">:-)</CODE> -<EMCLASS="emphasis">TOR</EM> ]</P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">ML</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="ch25_02.htm"TITLE="25.2 Four Ways to Skin a cat "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.2 Four Ways to Skin a cat "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="ch25_04.htm"TITLE='25.4 The "less" Pager: More than "more"'><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT='Next: 25.4 The "less" Pager: More than "more"'BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">25.2 Four Ways to Skin a cat </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">25.4 The "less" Pager: More than "more"</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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