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>7.5. Testing Your Knowledge of Tests</H1
><P
>The systemwide <TT
CLASS="FILENAME"
>xinitrc</TT
> file can be used
to launch the X server. This file contains quite a number
of <I
CLASS="FIRSTTERM"
>if/then</I
> tests. The following
is excerpted from an <SPAN
CLASS="QUOTE"
>"ancient"</SPAN
> version of
<TT
CLASS="FILENAME"
>xinitrc</TT
> (<I
CLASS="FIRSTTERM"
>Red Hat 7.1</I
>,
or thereabouts).</P
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>if [ -f $HOME/.Xclients ]; then
exec $HOME/.Xclients
elif [ -f /etc/X11/xinit/Xclients ]; then
exec /etc/X11/xinit/Xclients
else
# failsafe settings. Although we should never get here
# (we provide fallbacks in Xclients as well) it can't hurt.
xclock -geometry 100x100-5+5 &#38;
xterm -geometry 80x50-50+150 &#38;
if [ -f /usr/bin/netscape -a -f /usr/share/doc/HTML/index.html ]; then
netscape /usr/share/doc/HTML/index.html &#38;
fi
fi</PRE
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>Explain the <I
CLASS="FIRSTTERM"
>test</I
> constructs in the
above snippet, then examine an updated version of the
file, <TT
CLASS="FILENAME"
>/etc/X11/xinit/xinitrc</TT
>, and
analyze the <I
CLASS="FIRSTTERM"
>if/then</I
> test constructs
there. You may need to refer ahead to the discussions of <A
HREF="textproc.html#GREPREF"
>grep</A
>, <A
HREF="sedawk.html#SEDREF"
>sed</A
>,
and <A
HREF="regexp.html#REGEXREF"
>regular expressions</A
>.</P
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>Nested <TT
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>if/then</I
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> Condition Tests</TD
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