The biggest difference for general-purpose programming is that AWK supports floating-point arithmetic (and in some implementations arbitrary-precision arithmeti

The biggest difference for general-purpose programming is that AWK supports floating-point arithmetic (and in some implementations arbitrary-precision arithmetic), while bash does not. Shelling out to AWK is a much more portable approach to performing floating-point calculations in bash than "bc" or "dc", since it's available in more environments. Older versions of bash also have extremely limited or nonexistent support for associative arrays, which can pose challenges compared to AWK. I think AWK has much nicer, less surprising syntax than bash, but that's just a subjective opinion.