OPERANDS

The following operand shall be supported:

time
A non-negative decimal integer specifying the number of seconds for which to suspend execution.

IMPLEMENTATION NOTES
[..]
The sleep command will accept and honor a non-integer number of specified seconds
(with a `.' character as a decimal point). This is a non-portable extension, and its
use will nearly guarantee that a shell script will not execute properly on another
system.

SYNOPSIS
sleep NUMBER[SUFFIX]...
sleep OPTION

DESCRIPTION
Pause for NUMBER seconds. SUFFIX may be 's' for seconds (the default), 'm' for minutes,
'h' for hours or 'd' for days. Unlike most implementations that require NUMBER be an
integer, here NUMBER may be an arbitrary floating point number. Given two or more argu-
ments, pause for the amount of time specified by the sum of their values.