192 lines
3.2 KiB
HTML
192 lines
3.2 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML
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><HEAD
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><TITLE
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>Summary</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
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REL="HOME"
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TITLE="Bash Guide for Beginners"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Regular expressions"
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HREF="chap_04.html"><LINK
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REL="PREVIOUS"
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TITLE="Pattern matching using Bash features"
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HREF="sect_04_03.html"><LINK
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REL="NEXT"
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TITLE="Exercises"
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HREF="sect_04_05.html"></HEAD
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><BODY
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CLASS="sect1"
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BGCOLOR="#FFFFFF"
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TEXT="#000000"
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><TR
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COLSPAN="3"
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>Bash Guide for Beginners</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="sect_04_03.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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>Chapter 4. Regular expressions</TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="sect_04_05.html"
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>Next</A
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></TD
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></TR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><DIV
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CLASS="sect1"
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><H1
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CLASS="sect1"
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><A
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NAME="sect_04_04"
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></A
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>4.4. Summary</H1
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><P
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>Regular expressions are powerful tools for selecting particular lines from files or output. A lot of UNIX commands use regular expressions: <B
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CLASS="command"
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>vim</B
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>, <B
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CLASS="command"
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>perl</B
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>, the <SPAN
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CLASS="application"
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>PostgreSQL</SPAN
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> database and so on. They can be made available in any language or application using external libraries, and they even found their way to non-UNIX systems. For instance, regular expressions are used in the Excell spreadsheet that comes with the MicroSoft Windows Office suite. In this chapter we got the feel of the <B
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CLASS="command"
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>grep</B
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> command, which is indispensable in any UNIX environment.</P
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><DIV
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CLASS="note"
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><P
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></P
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><TABLE
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CLASS="note"
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BORDER="0"
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><TD
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WIDTH="25"
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ALIGN="CENTER"
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VALIGN="TOP"
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SRC="../images/note.gif"
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HSPACE="5"
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ALT="Note"></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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><P
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>The <B
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CLASS="command"
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>grep</B
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> command can do much more than the few tasks we discussed here; we only used it as an example for regular expressions. The GNU <B
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CLASS="command"
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>grep</B
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> version comes with plenty of documentation, which you are strongly advised to read!</P
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></TD
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></TR
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></TABLE
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></DIV
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><P
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>Bash has built-in features for matching patterns and can recognize character classes and ranges.</P
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></DIV
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><DIV
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WIDTH="33%"
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VALIGN="top"
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><A
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HREF="sect_04_03.html"
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ACCESSKEY="P"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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HREF="index.html"
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>Home</A
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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HREF="sect_04_05.html"
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ACCESSKEY="N"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>Pattern matching using Bash features</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="chap_04.html"
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>Up</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Exercises</TD
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></TR
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></TABLE
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></DIV
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></BODY
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></HTML
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> |