To convert from fractions to decimals in bash, do something like
myvar=`echo "scale=4; 5/10" | bc`
Then, to do a loop on that value,
for i in `seq 1 1000`; do sleep $myvar; done
My sleep implementation on Debian (GNU) seem to accept decimal sleep values.
Unfortunately..
With that kind of precision (4-5 decimal places), you're going to want something like a perl script or a compiled program; the overhead of calling any program within the loop is going to add a lot of jitter. Calling sleep itself will take a few milliseconds.
Consider the following, a 1/10,000ths of a second sleep, done 1000 times:
time for i in `seq 1 1000`; do sleep 0.0001; done
real 0m2.099s
user 0m3.080s
sys 0m1.464s
The expected result would be 1/10th of a second. Sleep has nowhere near the tolerances you want.
http://stackoverflow.com/questions/896904/how-do-i-sleep-for-a-millisecond-in-perl
using perl's Time::HiRes, 1000*1000 microseconds:
my $i=0;
for($i=0;$i<=1000;$i++) {
usleep(1000);
}
real 0m1.133s
user 0m0.024s
sys 0m0.012s
gives us much closer to a second.
