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<TITLE>BASH Programming - Introduction HOW-TO: User interfaces</TITLE>
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<H2><A NAME="s9">9. User interfaces</A> </H2>
<H2><A NAME="ss9.1">9.1 Using select to make simple menus</A>
</H2>
<P>
<BLOCKQUOTE><CODE>
<PRE>
#!/bin/bash
OPTIONS="Hello Quit"
select opt in $OPTIONS; do
if [ "$opt" = "Quit" ]; then
echo done
exit
elif [ "$opt" = "Hello" ]; then
echo Hello World
else
clear
echo bad option
fi
done
</PRE>
</CODE></BLOCKQUOTE>
<P> If you run this script you'll see that it is a
programmer's dream for text based menus. You'll probably notice
that it's very similar to the 'for' construction, only rather
than looping for each 'word' in $OPTIONS, it prompts the user.
<P>
<H2><A NAME="ss9.2">9.2 Using the command line </A>
</H2>
<P>
<BLOCKQUOTE><CODE>
<PRE>
#!/bin/bash
if [ -z "$1" ]; then
echo usage: $0 directory
exit
fi
SRCD=$1
TGTD="/var/backups/"
OF=home-$(date +%Y%m%d).tgz
tar -cZf $TGTD$OF $SRCD
</PRE>
</CODE></BLOCKQUOTE>
<P>
<P> What this script does should be clear to you. The expression
in the first conditional tests if the program has received an argument
($1) and quits if it didn't, showing the user a little usage message.
The rest of the script should be clear at this point.
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