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<HTML><!--Distributed by F --><HEAD><TITLE>[Chapter 25] 25.21 Numbering Lines </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="1998-08-04T21:43:33Z"><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_20.htm"TITLE="25.20 Printing the Top of a File "><LINKREL="next"HREF="ch26_01.htm"TITLE="26. Regular Expressions (Pattern Matching)"></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_20.htm"TITLE="25.20 Printing the Top of a File "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.20 Printing the Top of a File "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="CHAPTER"HREF="ch26_01.htm"TITLE="26. Regular Expressions (Pattern Matching)"><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 26. Regular Expressions (Pattern Matching)"BORDER="0"></A></TD></TR></TABLE> <HRALIGN="LEFT"WIDTH="515"TITLE="footer"></DIV><DIVCLASS="SECT1"><H2CLASS="sect1"><ACLASS="title"NAME="UPT-ART-7361">25.21 Numbering Lines </A></H2><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-28213"></A><ACLASS="indexterm"NAME="AUTOID-28215"></A><ACLASS="indexterm"NAME="AUTOID-28219"></A><ACLASS="indexterm"NAME="AUTOID-28221"></A>There are times when you want to print out a file with the linesnumbered - perhaps because you are showing a script or program indocumentation and want to refer to individual lines in the course ofyour discussion.</P><PCLASS="para">This is one of the handy things <EMCLASS="emphasis">cat</EM> can do for you, with the<EMCLASS="emphasis">-n</EM> option.</P><PCLASS="para"><EMCLASS="emphasis">cat -n</EM> precedes each line with some leading spaces, the linenumber, and a TAB.How many leading spaces?It depends on how highthe line numbers go.The line numbers are right justified at column 6, which means that a six-digit number will go all the way back tothe margin.I only belabor this point in case you're tempted to trimthe leading spaces with something like <SPANCLASS="link"><EMCLASS="emphasis">cut</EM> (<ACLASS="linkend"HREF="ch35_14.htm"TITLE="Cutting Columns or Fields with cut ">35.14</A>)</SPAN>.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-28232"></A>If you have a version of <EMCLASS="emphasis">cat</EM> that doesn't support <EMCLASS="emphasis">-n</EM>,try <EMCLASS="emphasis">nl</EM>, the line-numbering program.<EMCLASS="emphasis">nl -ba</EM> acts like <EMCLASS="emphasis">cat -n</EM>.By itself, <EMCLASS="emphasis">nl</EM> numbers only lines with text.</P><PCLASS="para"><ACLASS="indexterm"NAME="AUTOID-28241"></A><ACLASS="indexterm"NAME="AUTOID-28244"></A>You can achieve a similar effect with <EMCLASS="emphasis">pr -t -n</EM>.(The <EMCLASS="emphasis">-t</EM> keeps <EMCLASS="emphasis">pr</EM> from inserting the<SPANCLASS="link">header and footer (<ACLASS="linkend"HREF="ch43_07.htm"TITLE="Quick-and-Dirty Formatting Before Printing ">43.7</A>)</SPAN>it normally uses to break its output into pages.)And as long as we're giving you choices, here are four more <CODECLASS="literal">:-)</CODE>from Greg Ubben:</P><PCLASS="para"><BLOCKQUOTECLASS="screen"><PRECLASS="screen">grep -n \^awk '{print NR,$0}'sed = | sed 'N;s/\n/ /'ex - '+%#q'</PRE></BLOCKQUOTE></P><DIVCLASS="sect1info"><PCLASS="SECT1INFO">- <SPANCLASS="authorinitials">JP</SPAN>, <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="ch25_20.htm"TITLE="25.20 Printing the Top of a File "><IMGSRC="gifs/txtpreva.gif"SRC="gifs/txtpreva.gif"ALT="Previous: 25.20 Printing the Top of a File "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="CHAPTER"HREF="ch26_01.htm"TITLE="26. Regular Expressions (Pattern Matching)"><IMGSRC="gifs/txtnexta.gif"SRC="gifs/txtnexta.gif"ALT="Next: 26. Regular Expressions (Pattern Matching)"BORDER="0"></A></TD></TR><TR><TDALIGN="LEFT"VALIGN="TOP"WIDTH="172">25.20 Printing the Top of a File </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">26. 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