s6-portable-utils
Software
skarnet.org
 The s6-sleep program 
 s6-sleep sleeps for a given time, then optionally executes a program.
 Interface 
     s6-sleep [ -m ] time [ prog... ]
 -  s6-sleep acts as the generic
sleep utility.
It ignores non-lethal signals. 
-  If there are prog... arguments, then s6-sleep executes
into prog... after sleeping. Else, it exits 0. 
 Extra options 
 -  -m : Interpret time as milliseconds instead of seconds. 
 Posixness 
 s6-sleep is suitable as a Single Unix
sleep
program.