Assuming that the string passed in as the first positional parameter forms a valid arithmetic or logical expression, the float_test shell function returns exit status 0 if the expression evaluates to a non-zero value and returns exit status 1 if the expression evaluates to zero.

It could be written without the echo (and without redirection) if it used a BEGIN clause instead of an END clause:

Code:

float_test ( ) {
	awk 'BEGIN{exit(!('"$1"'))}'
}

If you're using a 1993 or later version of the Korn shell as your shell, you could evaluate similar expressions just using shell built-ins:

Code:

float_test ( ) {
	return $((!($1)))
}

But note that awk performs floating point arithmetic by default while ksh performs integer arithmetic by default. So, where float_test "1/3" using awk gives exit code 0 because 1/3 evaluates to 0.3333...; but when using ksh93 gives exit code 1 because 1/3 evaluates to 0. To reverse the behaviors, int(1/3) evaluates to 0 and exits with code 1 with awk and 1./3 evaluates to 0.3333... and exits with code 0 with ksh93.