360 lines
4.7 KiB
HTML
360 lines
4.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
<HTML
|
|
><HEAD
|
|
><TITLE
|
|
>The GNU awk programming language</TITLE
|
|
><META
|
|
NAME="GENERATOR"
|
|
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
|
|
REL="HOME"
|
|
TITLE="Bash Guide for Beginners"
|
|
HREF="index.html"><LINK
|
|
REL="PREVIOUS"
|
|
TITLE="Exercises"
|
|
HREF="sect_05_05.html"><LINK
|
|
REL="NEXT"
|
|
TITLE="Getting started with gawk"
|
|
HREF="sect_06_01.html"></HEAD
|
|
><BODY
|
|
CLASS="chapter"
|
|
BGCOLOR="#FFFFFF"
|
|
TEXT="#000000"
|
|
LINK="#0000FF"
|
|
VLINK="#840084"
|
|
ALINK="#0000FF"
|
|
><DIV
|
|
CLASS="NAVHEADER"
|
|
><TABLE
|
|
SUMMARY="Header navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TH
|
|
COLSPAN="3"
|
|
ALIGN="center"
|
|
>Bash Guide for Beginners</TH
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="left"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="sect_05_05.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="80%"
|
|
ALIGN="center"
|
|
VALIGN="bottom"
|
|
></TD
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="right"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="sect_06_01.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"></DIV
|
|
><DIV
|
|
CLASS="chapter"
|
|
><H1
|
|
><A
|
|
NAME="chap_06"
|
|
></A
|
|
>Chapter 6. The GNU awk programming language</H1
|
|
><DIV
|
|
CLASS="TOC"
|
|
><DL
|
|
><DT
|
|
><B
|
|
>Table of Contents</B
|
|
></DT
|
|
><DT
|
|
>6.1. <A
|
|
HREF="sect_06_01.html"
|
|
>Getting started with gawk</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>6.1.1. <A
|
|
HREF="sect_06_01.html#sect_06_01_01"
|
|
>What is gawk?</A
|
|
></DT
|
|
><DT
|
|
>6.1.2. <A
|
|
HREF="sect_06_01.html#sect_06_01_02"
|
|
>Gawk commands</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>6.2. <A
|
|
HREF="sect_06_02.html"
|
|
>The print program</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>6.2.1. <A
|
|
HREF="sect_06_02.html#sect_06_02_01"
|
|
>Printing selected fields</A
|
|
></DT
|
|
><DT
|
|
>6.2.2. <A
|
|
HREF="sect_06_02.html#sect_06_02_02"
|
|
>Formatting fields</A
|
|
></DT
|
|
><DT
|
|
>6.2.3. <A
|
|
HREF="sect_06_02.html#sect_06_02_03"
|
|
>The print command and regular expressions</A
|
|
></DT
|
|
><DT
|
|
>6.2.4. <A
|
|
HREF="sect_06_02.html#sect_06_02_04"
|
|
>Special patterns</A
|
|
></DT
|
|
><DT
|
|
>6.2.5. <A
|
|
HREF="sect_06_02.html#sect_06_02_05"
|
|
>Gawk scripts</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>6.3. <A
|
|
HREF="sect_06_03.html"
|
|
>Gawk variables</A
|
|
></DT
|
|
><DD
|
|
><DL
|
|
><DT
|
|
>6.3.1. <A
|
|
HREF="sect_06_03.html#sect_06_03_01"
|
|
>The input field separator</A
|
|
></DT
|
|
><DT
|
|
>6.3.2. <A
|
|
HREF="sect_06_03.html#sect_06_03_02"
|
|
>The output separators</A
|
|
></DT
|
|
><DT
|
|
>6.3.3. <A
|
|
HREF="sect_06_03.html#sect_06_03_03"
|
|
>The number of records</A
|
|
></DT
|
|
><DT
|
|
>6.3.4. <A
|
|
HREF="sect_06_03.html#sect_06_03_04"
|
|
>User defined variables</A
|
|
></DT
|
|
><DT
|
|
>6.3.5. <A
|
|
HREF="sect_06_03.html#sect_06_03_05"
|
|
>More examples</A
|
|
></DT
|
|
><DT
|
|
>6.3.6. <A
|
|
HREF="sect_06_03.html#sect_06_03_06"
|
|
>The printf program</A
|
|
></DT
|
|
></DL
|
|
></DD
|
|
><DT
|
|
>6.4. <A
|
|
HREF="sect_06_04.html"
|
|
>Summary</A
|
|
></DT
|
|
><DT
|
|
>6.5. <A
|
|
HREF="sect_06_05.html"
|
|
>Exercises</A
|
|
></DT
|
|
></DL
|
|
></DIV
|
|
><BLOCKQUOTE
|
|
CLASS="ABSTRACT"
|
|
><DIV
|
|
CLASS="abstract"
|
|
><A
|
|
NAME="AEN3998"
|
|
></A
|
|
><P
|
|
></P
|
|
><P
|
|
>In this chapter we will discuss:</P
|
|
><P
|
|
><P
|
|
></P
|
|
><UL
|
|
><LI
|
|
><P
|
|
>What is <SPAN
|
|
CLASS="application"
|
|
>gawk</SPAN
|
|
>?</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>Using <SPAN
|
|
CLASS="application"
|
|
>gawk</SPAN
|
|
> commands on the command line</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>How to format text with <SPAN
|
|
CLASS="application"
|
|
>gawk</SPAN
|
|
></P
|
|
></LI
|
|
><LI
|
|
><P
|
|
>How <SPAN
|
|
CLASS="application"
|
|
>gawk</SPAN
|
|
> uses regular expressions</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="application"
|
|
>Gawk</SPAN
|
|
> in scripts</P
|
|
></LI
|
|
><LI
|
|
><P
|
|
><SPAN
|
|
CLASS="application"
|
|
>Gawk</SPAN
|
|
> and variables</P
|
|
></LI
|
|
></UL
|
|
></P
|
|
><P
|
|
><DIV
|
|
CLASS="note"
|
|
><P
|
|
></P
|
|
><TABLE
|
|
CLASS="note"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="25"
|
|
ALIGN="CENTER"
|
|
VALIGN="TOP"
|
|
><IMG
|
|
SRC="../images/note.gif"
|
|
HSPACE="5"
|
|
ALT="Note"></TD
|
|
><TH
|
|
ALIGN="LEFT"
|
|
VALIGN="CENTER"
|
|
><B
|
|
>To make it more fun</B
|
|
></TH
|
|
></TR
|
|
><TR
|
|
><TD
|
|
> </TD
|
|
><TD
|
|
ALIGN="LEFT"
|
|
VALIGN="TOP"
|
|
><P
|
|
>As with <B
|
|
CLASS="command"
|
|
>sed</B
|
|
>, entire books have been written about various versions of <B
|
|
CLASS="command"
|
|
>awk</B
|
|
>. This introduction is far from complete and is only intended for understanding examples in the following chapters. For more information, best start with the documentation that comes with <SPAN
|
|
CLASS="application"
|
|
>GNU awk</SPAN
|
|
>: <SPAN
|
|
CLASS="QUOTE"
|
|
>"GAWK: Effective AWK Programming: A User's Guide for GNU Awk"</SPAN
|
|
>.</P
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
></P
|
|
><P
|
|
></P
|
|
></DIV
|
|
></BLOCKQUOTE
|
|
></DIV
|
|
><DIV
|
|
CLASS="NAVFOOTER"
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"><TABLE
|
|
SUMMARY="Footer navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="sect_05_05.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="index.html"
|
|
ACCESSKEY="H"
|
|
>Home</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="sect_06_01.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
>Exercises</TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
> </TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
>Getting started with gawk</TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
></BODY
|
|
></HTML
|
|
> |