On Thu, May 17, 2007 at 03:40:15AM +0000, Tyler Smith wrote: > On 2007-05-17, Bob McGowan <[EMAIL PROTECTED]> wrote: > > > > Some general comments, mostly aimed at making your code cleaner without > > changing what it does. > > > > First, both 'echo' and 'printf' put their results on standard out. Your > > call of 'printf' is inside command substitution, so its STDOUT becomes > > the command line for 'echo' which just prints to its STDOUT. Why the > > double print out? Just do: > > > > lab_let=$(printf "\\x$(echo $lab_num)") > > > > Next, the 'echo $lab_num' is not needed, $lab_num can stand alone: > > > > lab_let=$(printf "\\x$lab_num")
another thing to remember is you can enclose your variable names in {} so you
could do something like
lab_let=$(printf "\\x${lab_num}Moretext")
> >
> > And, the double quotes escape things, too, so the double backslash is
> > not needed:
> >
> > lab_let=$(printf "\x$lab_num")
> >
>
> Thank you for this! I started out with something a little more
> complicated, without the variable, trying to insert the hex character
> directly into another command. And my testing required that I use a
> form that would print something to the command line. I got very worked
> up trying to sort out the syntax, and obviously over-did it.
>
>
> > Then, the line where you increment lab_num can also be simpler. In bash
> > the $((...)) alone on a line will replace itself with the result
> > (command substitution, again). But, leave off the leading $ sign, and
> > it just does the increment:
> >
> > ((lab_num++))
>
> Oh, great, thanks. I added the echo to stop getting the complaint
> about unknown command, but this is better.
>
> >
> > So, cut and pasted from a bash shell:
> >
> > $ lab_num=41
> > $ lab_let=$(printf "\x$lab_num")
> > $ echo $lab_let
> > A
> > $ ((lab_num++))
> > $ lab_let=$(printf "\x$lab_num")
> > $ echo $lab_let
> > B
>
> Much improved!
>
> >
> > This would need two loops, the outer to increment the 'tens' digit, the
> > inner to increment the 'ones' digit, but it would do the trick. For
> > example:
> >
> > x=(0 1 2 3 4 5 6 7 8 9 A B C D E F)
> >
>
> I knew there was an array form in bash, but I couldn't find it. I'm
> working from the O'Reilly book classic shell scripting, and the only
> reference to arrays is in relation to awk scripts. This is a big help.
>
> Thanks alot!
>
> Tyler
>
>
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