399 lines
5.5 KiB
HTML
399 lines
5.5 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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>Invoking the script</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="Advanced Bash-Scripting Guide"
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HREF="index.html"><LINK
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REL="UP"
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TITLE="Starting Off With a Sha-Bang"
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HREF="sha-bang.html"><LINK
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REL="PREVIOUS"
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TITLE="Starting Off With a Sha-Bang"
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HREF="sha-bang.html"><LINK
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REL="NEXT"
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TITLE="Preliminary Exercises"
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HREF="prelimexer.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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LINK="#0000FF"
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VLINK="#840084"
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ALINK="#0000FF"
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><DIV
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SUMMARY="Header navigation table"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>Advanced Bash-Scripting Guide: </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="sha-bang.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 2. Starting Off With a Sha-Bang</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="prelimexer.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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></TABLE
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><HR
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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="INVOKING"
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></A
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>2.1. Invoking the script</H1
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><P
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>Having written the script, you can invoke it by <TT
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CLASS="USERINPUT"
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><B
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>sh
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scriptname</B
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></TT
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>,
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<A
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NAME="AEN300"
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HREF="#FTN.AEN300"
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><SPAN
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CLASS="footnote"
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>[1]</SPAN
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></A
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>
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or alternatively <TT
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CLASS="USERINPUT"
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><B
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>bash scriptname</B
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></TT
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>. (Not
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recommended is using <TT
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CLASS="USERINPUT"
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><B
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>sh <scriptname</B
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></TT
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>,
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since this effectively disables reading from
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<A
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HREF="ioredirintro.html#STDINOUTDEF"
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><TT
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CLASS="FILENAME"
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>stdin</TT
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></A
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>
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within the script.) Much more convenient is to make
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the script itself directly executable with a <A
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HREF="basic.html#CHMODREF"
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>chmod</A
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>.
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<P
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></P
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><DIV
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CLASS="VARIABLELIST"
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><DL
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><DT
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>Either:</DT
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><DD
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><P
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><TT
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CLASS="USERINPUT"
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><B
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>chmod 555 scriptname</B
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></TT
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> (gives
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everyone read/execute permission)
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<A
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NAME="AEN315"
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HREF="#FTN.AEN315"
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><SPAN
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CLASS="footnote"
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>[2]</SPAN
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></A
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>
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</P
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></DD
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><DT
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>or</DT
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><DD
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><P
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><TT
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CLASS="USERINPUT"
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><B
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>chmod +rx scriptname</B
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></TT
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> (gives
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everyone read/execute permission)</P
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><P
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><TT
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CLASS="USERINPUT"
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><B
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>chmod
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u+rx scriptname</B
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></TT
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> (gives only the
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script owner read/execute permission)</P
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></DD
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></DL
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></DIV
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>
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</P
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><P
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>Having made the script executable, you may now test it by
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<TT
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CLASS="USERINPUT"
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><B
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>./scriptname</B
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></TT
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>.
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<A
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NAME="AEN327"
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HREF="#FTN.AEN327"
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><SPAN
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CLASS="footnote"
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>[3]</SPAN
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></A
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>
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If it begins with a <SPAN
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CLASS="QUOTE"
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>"sha-bang"</SPAN
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> line, invoking the
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script calls the correct command interpreter to run it.</P
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><P
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>As a final step, after testing and debugging,
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you would likely want to move it to <TT
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CLASS="FILENAME"
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>/usr/local/bin</TT
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> (as
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<I
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CLASS="FIRSTTERM"
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>root</I
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>, of course), to make the script
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available to yourself and all other users as a systemwide
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executable. The script could then be invoked by simply typing
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<B
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CLASS="COMMAND"
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>scriptname</B
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> <B
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CLASS="KEYCAP"
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>[ENTER]</B
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> from the
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command-line.</P
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></DIV
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><H3
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CLASS="FOOTNOTES"
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>Notes</H3
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><TABLE
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BORDER="0"
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CLASS="FOOTNOTES"
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WIDTH="100%"
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><TR
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="5%"
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><A
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NAME="FTN.AEN300"
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HREF="invoking.html#AEN300"
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><SPAN
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CLASS="footnote"
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>[1]</SPAN
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></A
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></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="95%"
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><P
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>Caution: invoking a <I
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CLASS="FIRSTTERM"
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>Bash</I
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>
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script by <TT
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CLASS="USERINPUT"
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><B
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>sh scriptname</B
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></TT
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> turns off
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Bash-specific extensions, and the script may therefore fail
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to execute.</P
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></TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="5%"
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><A
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NAME="FTN.AEN315"
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HREF="invoking.html#AEN315"
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><SPAN
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CLASS="footnote"
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>[2]</SPAN
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></A
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></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="95%"
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><P
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>A script needs <I
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CLASS="FIRSTTERM"
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>read</I
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>, as
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well as execute permission for it to run, since the shell
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needs to be able to read it.</P
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></TD
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></TR
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><TR
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="5%"
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><A
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NAME="FTN.AEN327"
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HREF="invoking.html#AEN327"
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><SPAN
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CLASS="footnote"
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>[3]</SPAN
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></A
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></TD
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><TD
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ALIGN="LEFT"
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VALIGN="TOP"
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WIDTH="95%"
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><P
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>Why not simply invoke the script with
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<TT
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CLASS="USERINPUT"
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><B
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>scriptname</B
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></TT
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>? If the directory you
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are in (<A
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HREF="internalvariables.html#PWDREF"
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>$PWD</A
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>) is where
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<TT
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CLASS="FILENAME"
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>scriptname</TT
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> is located, why doesn't
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this work? This fails because, for security reasons, the
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current directory (<TT
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CLASS="FILENAME"
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>./</TT
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>)
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is not by default included in a user's <A
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HREF="internalvariables.html#PATHREF"
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>$PATH</A
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>. It is therefore necessary to
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explicitly invoke the script in the current directory with
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a <TT
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CLASS="USERINPUT"
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><B
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>./scriptname</B
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></TT
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>.</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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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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SUMMARY="Footer navigation table"
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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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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><A
|
|
HREF="sha-bang.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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><A
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HREF="index.html"
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ACCESSKEY="H"
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>Home</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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><A
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HREF="prelimexer.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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>Starting Off With a Sha-Bang</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="sha-bang.html"
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ACCESSKEY="U"
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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"
|
|
>Preliminary 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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> |