What happens to sleep for milliseconds?

sleep is a very popular command and we can start sleep from 1 second.

# wait one second please
sleep 1

but what the alternative if I need to wait only 0.1 second or between 0.1 to 1 second ?

• remark: on linux or OS X sleep 0.XXX works fine , but on solaris sleep 0.1 or sleep 0.01 - illegal syntax

The documentation for the sleep command from coreutils says.

Historical implementations of sleep have required that number be an integer, and only accepted a single argument without a suffix. However, GNU sleep accepts arbitrary floating point numbers. See Floating point.

Hence you can use sleep 0.1 , sleep 1.0e-1 and similar arguments.