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$lab_num") > > And, the double quotes escape things, too, so the double backslash is > not needed: > > lab_let=$(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 -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
