On Mon, Dec 07, 2009 at 05:08:02PM -0800, DennisW wrote: > Since printf understands floats (or acts like it does), you can use it > plus a little care and luck to do float comparisons in Bash: > [...] > $ printf -v a "%08.2f" $a > $ printf -v b "%08.2f" $b > $ [[ $a < $b ]] && echo true || echo false > false # CORRECT > echo "$a $b" > 00147.10 00023.00
While this is certainly clever, it requires some knowledge of the possible range of values being compared, so that one can construct a suitable printf format specifier. Any unexpectedly large or small input would break it. Real floating-point comparisons require the services of an external program (such as bc or awk) since bash has no built-in support for it. (Or a loadable bash builtin, but very few people use those.)
