This is probably not the easiest solution, but the first thing that comes to mind is to use printf. Unfortunately, printf requires octal values, so you need to translate. To print A (decimal value of ascii 65), you can use dc to calculate the octal number and do the following:
$ A = 65
$ printf \\ $ (echo 8o $ {A} p | dc)
If you want to use perl:
$ perl -e "print chr $ A" # print character whose decimal value is stored in shell variable A
$ perl -e 'print chr 10' # print a carriage return
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